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Message-ID: <9a1b404d118fb5ced3e627b32b5ceace6804f092.camel@redhat.com>
Subject: Re: [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info
 into the atomic state
From:   Lyude Paul <lyude@redhat.com>
To:     "Lin, Wayne" <Wayne.Lin@amd.com>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "nouveau@lists.freedesktop.org" <nouveau@lists.freedesktop.org>,
        "amd-gfx@lists.freedesktop.org" <amd-gfx@lists.freedesktop.org>
Cc:     Ville =?ISO-8859-1?Q?Syrj=E4l=E4?= 
        <ville.syrjala@linux.intel.com>, "Zuo, Jerry" <Jerry.Zuo@amd.com>,
        Jani Nikula <jani.nikula@intel.com>,
        Imre Deak <imre.deak@intel.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Sean Paul <sean@poorly.run>,
        "Wentland, Harry" <Harry.Wentland@amd.com>,
        "Li, Sun peng (Leo)" <Sunpeng.Li@amd.com>,
        "Siqueira, Rodrigo" <Rodrigo.Siqueira@amd.com>,
        "Deucher, Alexander" <Alexander.Deucher@amd.com>,
        "Koenig, Christian" <Christian.Koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Karol Herbst <kherbst@redhat.com>,
        "Kazlauskas, Nicholas" <Nicholas.Kazlauskas@amd.com>,
        "Li, Roman" <Roman.Li@amd.com>, "Shih, Jude" <Jude.Shih@amd.com>,
        Simon Ser <contact@emersion.fr>,
        "Lakha, Bhawanpreet" <Bhawanpreet.Lakha@amd.com>,
        Mikita Lipski <mikita.lipski@amd.com>,
        Claudio Suarez <cssk@net-c.es>, "Chen, Ian" <Ian.Chen@amd.com>,
        Colin Ian King <colin.king@intel.com>,
        "Wu, Hersen" <hersenxs.wu@amd.com>,
        "Liu, Wenjing" <Wenjing.Liu@amd.com>, "Lei, Jun" <Jun.Lei@amd.com>,
        "Strauss, Michael" <Michael.Strauss@amd.com>,
        "Ma, Leo" <Hanghong.Ma@amd.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        =?ISO-8859-1?Q?Jos=E9?= Roberto de Souza 
        <jose.souza@intel.com>, He Ying <heying24@huawei.com>,
        Anshuman Gupta <anshuman.gupta@intel.com>,
        Andi Shyti <andi.shyti@linux.intel.com>,
        Ashutosh Dixit <ashutosh.dixit@intel.com>,
        Juston Li <juston.li@intel.com>,
        Sean Paul <seanpaul@chromium.org>,
        Fernando Ramos <greenfoo@u92.eu>,
        Luo Jiaxing <luojiaxing@huawei.com>,
        Javier Martinez Canillas <javierm@redhat.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:INTEL DRM DRIVERS" <intel-gfx@lists.freedesktop.org>
Date:   Wed, 06 Jul 2022 17:57:25 -0400
In-Reply-To: <CO6PR12MB5489BAFF2DDCD67F8BDCD827FC819@CO6PR12MB5489.namprd12.prod.outlook.com>
References: <20220607192933.1333228-1-lyude@redhat.com>
         <20220607192933.1333228-19-lyude@redhat.com>
         <CO6PR12MB5489BAFF2DDCD67F8BDCD827FC819@CO6PR12MB5489.namprd12.prod.outlook.com>
Organization: Red Hat Inc.
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On Tue, 2022-07-05 at 09:10 +0000, Lin, Wayne wrote:
> [Public]
> 
> 
> 
> > -----Original Message-----
> > From: Lyude Paul <lyude@redhat.com>
> > Sent: Wednesday, June 8, 2022 3:30 AM
> > To: dri-devel@lists.freedesktop.org; nouveau@lists.freedesktop.org; amd-
> > gfx@lists.freedesktop.org
> > Cc: Lin, Wayne <Wayne.Lin@amd.com>; Ville Syrjälä
> > <ville.syrjala@linux.intel.com>; Zuo, Jerry <Jerry.Zuo@amd.com>; Jani
> > Nikula
> > <jani.nikula@intel.com>; Imre Deak <imre.deak@intel.com>; Daniel Vetter
> > <daniel.vetter@ffwll.ch>; Sean Paul <sean@poorly.run>; Wentland, Harry
> > <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>;
> > Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander
> > <Alexander.Deucher@amd.com>; Koenig, Christian
> > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David
> > Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Jani Nikula
> > <jani.nikula@linux.intel.com>; Joonas Lahtinen
> > <joonas.lahtinen@linux.intel.com>; Rodrigo Vivi <rodrigo.vivi@intel.com>;
> > Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Ben Skeggs
> > <bskeggs@redhat.com>; Karol Herbst <kherbst@redhat.com>; Kazlauskas,
> > Nicholas <Nicholas.Kazlauskas@amd.com>; Li, Roman
> > <Roman.Li@amd.com>; Shih, Jude <Jude.Shih@amd.com>; Simon Ser
> > <contact@emersion.fr>; Lakha, Bhawanpreet
> > <Bhawanpreet.Lakha@amd.com>; Mikita Lipski <mikita.lipski@amd.com>;
> > Claudio Suarez <cssk@net-c.es>; Chen, Ian <Ian.Chen@amd.com>; Colin Ian
> > King <colin.king@intel.com>; Wu, Hersen <hersenxs.wu@amd.com>; Liu,
> > Wenjing <Wenjing.Liu@amd.com>; Lei, Jun <Jun.Lei@amd.com>; Strauss,
> > Michael <Michael.Strauss@amd.com>; Ma, Leo <Hanghong.Ma@amd.com>;
> > Thomas Zimmermann <tzimmermann@suse.de>; José Roberto de Souza
> > <jose.souza@intel.com>; He Ying <heying24@huawei.com>; Anshuman
> > Gupta <anshuman.gupta@intel.com>; Andi Shyti
> > <andi.shyti@linux.intel.com>; Ashutosh Dixit <ashutosh.dixit@intel.com>;
> > Juston Li <juston.li@intel.com>; Sean Paul <seanpaul@chromium.org>;
> > Fernando Ramos <greenfoo@u92.eu>; Luo Jiaxing
> > <luojiaxing@huawei.com>; Javier Martinez Canillas <javierm@redhat.com>;
> > open list <linux-kernel@vger.kernel.org>; open list:INTEL DRM DRIVERS
> > <intel-gfx@lists.freedesktop.org>
> > Subject: [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into
> > the atomic state
> > 
> > Now that we've finally gotten rid of the non-atomic MST users leftover in
> > the kernel, we can finally get rid of all of the legacy payload code we
> > have and move as much as possible into the MST atomic state structs. The
> > main purpose of this is to make the MST code a lot less confusing to work
> > on, as there's a lot of duplicated logic that doesn't really need to be
> > here. As well, this should make introducing features like fallback link
> > retraining and DSC support far easier.
> > 
> > Since the old payload code was pretty gnarly and there's a Lot of changes
> > here, I expect this might be a bit difficult to review. So to make things
> > as easy as possible for reviewers, I'll sum up how both the old and new
> > code worked here (it took me a while to figure this out too!).
> > 
> > The old MST code basically worked by maintaining two different payload
> > tables - proposed_vcpis, and payloads. proposed_vcpis would hold the
> > modified payload we wanted to push to the topology, while payloads held
> > the
> > payload table that was currently programmed in hardware. Modifications to
> > proposed_vcpis would be handled through drm_dp_allocate_vcpi(),
> > drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then,
> > they
> > would be pushed via drm_dp_mst_update_payload_step1() and
> > drm_dp_mst_update_payload_step2().
> > 
> > Furthermore, it's important to note how adding and removing VC payloads
> > actually worked with drm_dp_mst_update_payload_step1(). When a VC
> > payload
> > is removed from the VC table, all VC payloads which come after the removed
> > VC payload's slots must have their time slots shifted towards the start of
> > the table. The old code handles this by looping through the entire payload
> > table and recomputing the start slot for every payload in the topology
> > from
> > scratch. While very much overkill, this ends up doing the right thing
> > because we always order the VCPIs for payloads from first to last starting
> > timeslot.
> > 
> > It's important to also note that drm_dp_mst_update_payload_step2() isn't
> > actually limited to updating a single payload - the driver can use it to
> > queue up multiple payload changes so that as many of them can be sent as
> > possible before waiting for the ACT.
> 
> Hi Lyude,
> 
> I have concern for updating payload table multiple times for multiple
> payload
> changes before sending the ACT. Also consult with one branch vendor, they 
> say their fw will expect receiving one ALLOCATE_PAYLOAD after setting DPCD
> 002c0h bit 0 (VC payload ID table updated).

Ooooh, nice catch! Originally when I looked at amdgpu's MST stream updating
code I had thought that amdgpu was performing multiple updates per-ACT, but it
seems I must have misread something as upon reinspection that doesn't appear
to be the case.

FWIW nouveau does actually do this (iirc it's -technically- allowed in the
spec MST spec), but seeing as apparently not all hub vendors implement
supporting multiple payloads per-ACT correctly it sounds like we should
probably remove that behavior entirely. I wonder if we should also poke VESA
about this, so they know to mention that not all devices in the field will
work with this.

Anyway, thanks for the catch! I will definitely fix this up in the next
version of this series so we always do one ACT per payload update.

> 
> Thanks!
> > 
> > drm_dp_mst_update_payload_step2() is pretty self explanatory and
> > basically
> > the same between the old and new code, save for the fact we don't have a
> > second step for deleting payloads anymore -and thus rename it to
> > drm_dp_mst_add_payload_step2().
> > 
> > The new payload code stores all of the current payload info within the MST
> > atomic state and computes as much of the state as possible ahead of time.
> > This has the one exception of the starting timeslots for payloads, which
> > can't be determined at atomic check time since the starting time slots
> > will
> > vary depending on what order CRTCs are enabled in the atomic state - which
> > varies from driver to driver. These are still stored in the atomic MST
> > state, but are only copied from the old MST state during atomic commit
> > time. Likewise, this is when new start slots are determined.
> > 
> > Adding/removing payloads now works much more closely to how things are
> > described in the spec. When we delete a payload, we loop through the
> > current list of payloads and update the start slots for any payloads whose
> > time slots came after the payload we just deleted. Determining the
> > starting
> > time slots for new payloads being added is done by simply keeping track of
> > where the end of the VC table is in
> > drm_dp_mst_topology_mgr->next_start_slot. Additionally, it's worth noting
> > that we no longer have a single update_payload() function. Instead, we now
> > have drm_dp_mst_add_payload_step1|2() and
> > drm_dp_mst_remove_payload(). As
> > such, it's now left it up to the driver to figure out when to add or
> > remove
> > payloads. The driver already knows when it's disabling/enabling CRTCs, so
> > it also already knows when payloads should be added or removed. And, this
> > doesn't interfere with the ability to queue up multiple payload changes
> > before waiting for the ACT.
> > 
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > Cc: Wayne Lin <Wayne.Lin@amd.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Imre Deak <imre.deak@intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Sean Paul <sean@poorly.run>
> > ---
> >  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  56 +-
> >  .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 107 +--
> >  .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  85 +--
> >  .../amd/display/include/link_service_types.h  |   7 +
> >  drivers/gpu/drm/display/drm_dp_mst_topology.c | 699 ++++++------------
> >  drivers/gpu/drm/i915/display/intel_dp_mst.c   |  64 +-
> >  drivers/gpu/drm/i915/display/intel_hdcp.c     |  24 +-
> >  drivers/gpu/drm/nouveau/dispnv50/disp.c       | 163 ++--
> >  include/drm/display/drm_dp_mst_helper.h       | 178 ++---
> >  9 files changed, 536 insertions(+), 847 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index ac8648e3c1c9..93d572ea3c48 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -7378,6 +7378,7 @@ static int dm_encoder_helper_atomic_check(struct
> > drm_encoder *encoder,
> >         const struct drm_display_mode *adjusted_mode = &crtc_state-
> > > adjusted_mode;
> >         struct drm_dp_mst_topology_mgr *mst_mgr;
> >         struct drm_dp_mst_port *mst_port;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         enum dc_color_depth color_depth;
> >         int clock, bpp = 0;
> >         bool is_y420 = false;
> > @@ -7391,6 +7392,13 @@ static int
> > dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
> >         if (!crtc_state->connectors_changed && !crtc_state-
> > > mode_changed)
> >                 return 0;
> > 
> > +       mst_state = drm_atomic_get_mst_topology_state(state, mst_mgr);
> > +       if (IS_ERR(mst_state))
> > +               return PTR_ERR(mst_state);
> > +
> > +       if (!mst_state->pbn_div)
> > +               mst_state->pbn_div =
> > dm_mst_get_pbn_divider(aconnector->mst_port->dc_link);
> > +
> >         if (!state->duplicated) {
> >                 int max_bpc = conn_state->max_requested_bpc;
> >                 is_y420 = drm_mode_is_420_also(&connector->display_info,
> > adjusted_mode) &&
> > @@ -7402,11 +7410,10 @@ static int
> > dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
> >                 clock = adjusted_mode->clock;
> >                 dm_new_connector_state->pbn =
> > drm_dp_calc_pbn_mode(clock, bpp, false);
> >         }
> > -       dm_new_connector_state->vcpi_slots =
> > drm_dp_atomic_find_time_slots(state,
> > -
> > mst_mgr,
> > -
> > mst_port,
> > -
> > dm_new_connector_state->pbn,
> > -
> > dm_mst_get_pbn_divider(aconnector->dc_link));
> > +
> > +       dm_new_connector_state->vcpi_slots =
> > +               drm_dp_atomic_find_time_slots(state, mst_mgr, mst_port,
> > +                                             dm_new_connector_state-
> > >pbn);
> >         if (dm_new_connector_state->vcpi_slots < 0) {
> >                 DRM_DEBUG_ATOMIC("failed finding vcpi slots: %d\n",
> > (int)dm_new_connector_state->vcpi_slots);
> >                 return dm_new_connector_state->vcpi_slots;
> > @@ -7476,18 +7483,12 @@ static int
> > dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state,
> >                         dm_conn_state->pbn = pbn;
> >                         dm_conn_state->vcpi_slots = slot_num;
> > 
> > -                       drm_dp_mst_atomic_enable_dsc(state,
> > -                                                    aconnector->port,
> > -                                                    dm_conn_state->pbn,
> > -                                                    0,
> > +                       drm_dp_mst_atomic_enable_dsc(state, aconnector-
> > > port, dm_conn_state->pbn,
> >                                                      false);
> >                         continue;
> >                 }
> > 
> > -               vcpi = drm_dp_mst_atomic_enable_dsc(state,
> > -                                                   aconnector->port,
> > -                                                   pbn, pbn_div,
> > -                                                   true);
> > +               vcpi = drm_dp_mst_atomic_enable_dsc(state, aconnector-
> > > port, pbn, true);
> >                 if (vcpi < 0)
> >                         return vcpi;
> > 
> > @@ -10943,8 +10944,6 @@ static int amdgpu_dm_atomic_check(struct
> > drm_device *dev,
> >         struct dm_crtc_state *dm_old_crtc_state, *dm_new_crtc_state;
> >  #if defined(CONFIG_DRM_AMD_DC_DCN)
> >         struct dsc_mst_fairness_vars vars[MAX_PIPES];
> > -       struct drm_dp_mst_topology_state *mst_state;
> > -       struct drm_dp_mst_topology_mgr *mgr;
> >  #endif
> > 
> >         trace_amdgpu_dm_atomic_check_begin(state);
> > @@ -11180,33 +11179,6 @@ static int amdgpu_dm_atomic_check(struct
> > drm_device *dev,
> >                 lock_and_validation_needed = true;
> >         }
> > 
> > -#if defined(CONFIG_DRM_AMD_DC_DCN)
> > -       /* set the slot info for each mst_state based on the link encoding
> > format */
> > -       for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> > -               struct amdgpu_dm_connector *aconnector;
> > -               struct drm_connector *connector;
> > -               struct drm_connector_list_iter iter;
> > -               u8 link_coding_cap;
> > -
> > -               if (!mgr->mst_state )
> > -                       continue;
> > -
> > -               drm_connector_list_iter_begin(dev, &iter);
> > -               drm_for_each_connector_iter(connector, &iter) {
> > -                       int id = connector->index;
> > -
> > -                       if (id == mst_state->mgr->conn_base_id) {
> > -                               aconnector =
> > to_amdgpu_dm_connector(connector);
> > -                               link_coding_cap =
> > dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link);
> > -                               drm_dp_mst_update_slots(mst_state,
> > link_coding_cap);
> > -
> > -                               break;
> > -                       }
> > -               }
> > -               drm_connector_list_iter_end(&iter);
> > -
> > -       }
> > -#endif
> >         /**
> >          * Streams and planes are reset when there are changes that affect
> >          * bandwidth. Anything that affects bandwidth needs to go through
> > diff --git
> > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > index 1eaacab0334b..f843fd86787f 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > @@ -27,6 +27,7 @@
> >  #include <linux/acpi.h>
> >  #include <linux/i2c.h>
> > 
> > +#include <drm/drm_atomic.h>
> >  #include <drm/drm_probe_helper.h>
> >  #include <drm/amdgpu_drm.h>
> >  #include <drm/drm_edid.h>
> > @@ -154,40 +155,32 @@ enum dc_edid_status
> > dm_helpers_parse_edid_caps(
> >  }
> > 
> >  static void
> > -fill_dc_mst_payload_table_from_drm(struct amdgpu_dm_connector
> > *aconnector,
> > -                                  struct
> > dc_dp_mst_stream_allocation_table
> > *proposed_table)
> > +fill_dc_mst_payload_table_from_drm(struct drm_dp_mst_topology_state
> > *mst_state,
> > +                                  struct amdgpu_dm_connector *aconnector,
> > +                                  struct
> > dc_dp_mst_stream_allocation_table
> > *table)
> >  {
> > +       struct dc_dp_mst_stream_allocation_table new_table = { 0 };
> > +       struct dc_dp_mst_stream_allocation *sa;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         int i;
> > -       struct drm_dp_mst_topology_mgr *mst_mgr =
> > -                       &aconnector->mst_port->mst_mgr;
> > 
> > -       mutex_lock(&mst_mgr->payload_lock);
> > -
> > -       proposed_table->stream_count = 0;
> > -
> > -       /* number of active streams */
> > -       for (i = 0; i < mst_mgr->max_payloads; i++) {
> > -               if (mst_mgr->payloads[i].num_slots == 0)
> > -                       break; /* end of vcp_id table */
> > -
> > -               ASSERT(mst_mgr->payloads[i].payload_state !=
> > -                               DP_PAYLOAD_DELETE_LOCAL);
> > -
> > -               if (mst_mgr->payloads[i].payload_state ==
> > DP_PAYLOAD_LOCAL ||
> > -                       mst_mgr->payloads[i].payload_state ==
> > -                                       DP_PAYLOAD_REMOTE) {
> > -
> > -                       struct dc_dp_mst_stream_allocation *sa =
> > -                                       &proposed_table-
> > > stream_allocations[
> > -                                               proposed_table-
> > > stream_count];
> > -
> > -                       sa->slot_count = mst_mgr->payloads[i].num_slots;
> > -                       sa->vcp_id = mst_mgr->proposed_vcpis[i]->vcpi;
> > -                       proposed_table->stream_count++;
> > -               }
> > +       /* Copy over payloads */
> > +       list_for_each_entry(payload, &mst_state->payloads, next) {
> > +               if (payload->delete)
> > +                       continue;
> > +
> > +               sa =
> > &new_table.stream_allocations[new_table.stream_count];
> > +               sa->slot_count = payload->time_slots;
> > +               sa->vcp_id = payload->vcpi;
> > +               sa->port = payload->port;
> > +               drm_dp_mst_get_port_malloc(sa->port);
> > +               new_table.stream_count++;
> >         }
> > 
> > -       mutex_unlock(&mst_mgr->payload_lock);
> > +       /* Release the old table, and copy over the new one */
> > +       for (i = 0; i < table->stream_count; i++)
> > +               drm_dp_mst_put_port_malloc(table-
> > > stream_allocations[i].port);
> > +       *table = new_table;
> >  }
> > 
> >  void dm_helpers_dp_update_branch_info(
> > @@ -205,11 +198,9 @@ bool
> > dm_helpers_dp_mst_write_payload_allocation_table(
> >                 bool enable)
> >  {
> >         struct amdgpu_dm_connector *aconnector;
> > -       struct dm_connector_state *dm_conn_state;
> > +       struct drm_dp_mst_topology_state *mst_state;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         struct drm_dp_mst_topology_mgr *mst_mgr;
> > -       struct drm_dp_mst_port *mst_port;
> > -       bool ret;
> > -       u8 link_coding_cap = DP_8b_10b_ENCODING;
> > 
> >         aconnector = (struct amdgpu_dm_connector *)stream-
> > > dm_stream_context;
> >         /* Accessing the connector state is required for vcpi_slots
> > allocation
> > @@ -220,40 +211,21 @@ bool
> > dm_helpers_dp_mst_write_payload_allocation_table(
> >         if (!aconnector || !aconnector->mst_port)
> >                 return false;
> > 
> > -       dm_conn_state = to_dm_connector_state(aconnector->base.state);
> > -
> >         mst_mgr = &aconnector->mst_port->mst_mgr;
> > -
> > -       if (!mst_mgr->mst_state)
> > -               return false;
> > -
> > -       mst_port = aconnector->port;
> > -
> > -#if defined(CONFIG_DRM_AMD_DC_DCN)
> > -       link_coding_cap =
> > dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link);
> > -#endif
> > -
> > -       if (enable) {
> > -
> > -               ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port,
> > -                                              dm_conn_state->pbn,
> > -                                              dm_conn_state->vcpi_slots);
> > -               if (!ret)
> > -                       return false;
> > -
> > -       } else {
> > -               drm_dp_mst_reset_vcpi_slots(mst_mgr, mst_port);
> > -       }
> > +       mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
> > 
> >         /* It's OK for this to fail */
> > -       drm_dp_update_payload_part1(mst_mgr, (link_coding_cap ==
> > DP_CAP_ANSI_128B132B) ? 0:1);
> > +       payload = drm_atomic_get_mst_payload_state(mst_state,
> > aconnector->port);
> > +       if (enable)
> > +               drm_dp_add_payload_part1(mst_mgr, mst_state, payload);
> > +       else
> > +               drm_dp_remove_payload(mst_mgr, mst_state, payload);
> > 
> >         /* mst_mgr->->payloads are VC payload notify MST branch using
> > DPCD or
> >          * AUX message. The sequence is slot 1-63 allocated sequence for
> > each
> >          * stream. AMD ASIC stream slot allocation should follow the same
> >          * sequence. copy DRM MST allocation to dc */
> > -
> > -       fill_dc_mst_payload_table_from_drm(aconnector, proposed_table);
> > +       fill_dc_mst_payload_table_from_drm(mst_state, aconnector,
> > proposed_table);
> > 
> >         return true;
> >  }
> > @@ -310,26 +282,23 @@ bool
> > dm_helpers_dp_mst_send_payload_allocation(
> >                 bool enable)
> >  {
> >         struct amdgpu_dm_connector *aconnector;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct drm_dp_mst_topology_mgr *mst_mgr;
> > -       struct drm_dp_mst_port *mst_port;
> > +       struct drm_dp_mst_atomic_payload *payload;
> > 
> >         aconnector = (struct amdgpu_dm_connector *)stream-
> > > dm_stream_context;
> > 
> >         if (!aconnector || !aconnector->mst_port)
> >                 return false;
> > 
> > -       mst_port = aconnector->port;
> > -
> >         mst_mgr = &aconnector->mst_port->mst_mgr;
> > -
> > -       if (!mst_mgr->mst_state)
> > -               return false;
> > +       mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
> > 
> >         /* It's OK for this to fail */
> > -       drm_dp_update_payload_part2(mst_mgr);
> > -
> > -       if (!enable)
> > -               drm_dp_mst_deallocate_vcpi(mst_mgr, mst_port);
> > +       if (enable) {
> > +               payload = drm_atomic_get_mst_payload_state(mst_state,
> > aconnector->port);
> > +               drm_dp_add_payload_part2(mst_mgr, mst_state-
> > > base.state, payload);
> > +       }
> > 
> >         return true;
> >  }
> > diff --git
> > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > index b447c453b58d..18de4a98df40 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > +++
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > @@ -501,15 +501,8 @@ void amdgpu_dm_initialize_dp_connector(struct
> > amdgpu_display_manager *dm,
> > 
> >         dc_link_dp_get_max_link_enc_cap(aconnector->dc_link,
> > &max_link_enc_cap);
> >         aconnector->mst_mgr.cbs = &dm_mst_cbs;
> > -       drm_dp_mst_topology_mgr_init(
> > -               &aconnector->mst_mgr,
> > -               adev_to_drm(dm->adev),
> > -               &aconnector->dm_dp_aux.aux,
> > -               16,
> > -               4,
> > -               max_link_enc_cap.lane_count,
> > -
> >         drm_dp_bw_code_to_link_rate(max_link_enc_cap.link_rate),
> > -               aconnector->connector_id);
> > +       drm_dp_mst_topology_mgr_init(&aconnector->mst_mgr,
> > adev_to_drm(dm->adev),
> > +                                    &aconnector->dm_dp_aux.aux, 16, 4,
> > aconnector->connector_id);
> > 
> >         drm_connector_attach_dp_subconnector_property(&aconnector-
> > > base);
> >  }
> > @@ -614,6 +607,7 @@ static int bpp_x16_from_pbn(struct
> > dsc_mst_fairness_params param, int pbn)
> >  }
> > 
> >  static void increase_dsc_bpp(struct drm_atomic_state *state,
> > +                            struct drm_dp_mst_topology_state *mst_state,
> >                              struct dc_link *dc_link,
> >                              struct dsc_mst_fairness_params *params,
> >                              struct dsc_mst_fairness_vars *vars,
> > @@ -626,12 +620,9 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >         int min_initial_slack;
> >         int next_index;
> >         int remaining_to_increase = 0;
> > -       int pbn_per_timeslot;
> >         int link_timeslots_used;
> >         int fair_pbn_alloc;
> > 
> > -       pbn_per_timeslot = dm_mst_get_pbn_divider(dc_link);
> > -
> >         for (i = 0; i < count; i++) {
> >                 if (vars[i + k].dsc_enabled) {
> >                         initial_slack[i] =
> > @@ -662,17 +653,17 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                 link_timeslots_used = 0;
> > 
> >                 for (i = 0; i < count; i++)
> > -                       link_timeslots_used += DIV_ROUND_UP(vars[i +
> > k].pbn, pbn_per_timeslot);
> > +                       link_timeslots_used += DIV_ROUND_UP(vars[i +
> > k].pbn, mst_state->pbn_div);
> > 
> > -               fair_pbn_alloc = (63 - link_timeslots_used) /
> > remaining_to_increase * pbn_per_timeslot;
> > +               fair_pbn_alloc =
> > +                       (63 - link_timeslots_used) / remaining_to_increase
> > *
> > mst_state->pbn_div;
> > 
> >                 if (initial_slack[next_index] > fair_pbn_alloc) {
> >                         vars[next_index].pbn += fair_pbn_alloc;
> >                         if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -                                                        
> > pbn_per_timeslot) <
> > 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                 return;
> >                         if (!drm_dp_mst_atomic_check(state)) {
> >                                 vars[next_index].bpp_x16 =
> > bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
> > @@ -681,8 +672,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                                 if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -
> > pbn_per_timeslot) < 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                         return;
> >                         }
> >                 } else {
> > @@ -690,8 +680,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                         if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -                                                        
> > pbn_per_timeslot) <
> > 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                 return;
> >                         if (!drm_dp_mst_atomic_check(state)) {
> >                                 vars[next_index].bpp_x16 =
> > params[next_index].bw_range.max_target_bpp_x16;
> > @@ -700,8 +689,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                                 if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -
> > pbn_per_timeslot) < 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                         return;
> >                         }
> >                 }
> > @@ -757,8 +745,7 @@ static void try_disable_dsc(struct drm_atomic_state
> > *state,
> >                 if (drm_dp_atomic_find_time_slots(state,
> >                                                   params[next_index].port-
> > > mgr,
> >                                                   params[next_index].port,
> > -                                                 vars[next_index].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +                                                 vars[next_index].pbn) <
> > 0)
> >                         return;
> > 
> >                 if (!drm_dp_mst_atomic_check(state)) {
> > @@ -769,8 +756,7 @@ static void try_disable_dsc(struct drm_atomic_state
> > *state,
> >                         if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                 return;
> >                 }
> > 
> > @@ -783,17 +769,27 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                                              struct dc_state *dc_state,
> >                                              struct dc_link *dc_link,
> >                                              struct dsc_mst_fairness_vars
> > *vars,
> > +                                            struct
> > drm_dp_mst_topology_mgr
> > *mgr,
> >                                              int *link_vars_start_index)
> >  {
> > -       int i, k;
> >         struct dc_stream_state *stream;
> >         struct dsc_mst_fairness_params params[MAX_PIPES];
> >         struct amdgpu_dm_connector *aconnector;
> > +       struct drm_dp_mst_topology_state *mst_state =
> > drm_atomic_get_mst_topology_state(state, mgr);
> >         int count = 0;
> > +       int i, k;
> >         bool debugfs_overwrite = false;
> > 
> >         memset(params, 0, sizeof(params));
> > 
> > +       if (IS_ERR(mst_state))
> > +               return false;
> > +
> > +       mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link);
> > +#if defined(CONFIG_DRM_AMD_DC_DCN)
> > +       drm_dp_mst_update_slots(mst_state,
> > dc_link_dp_mst_decide_link_encoding_format(dc_link));
> > +#endif
> > +
> >         /* Set up params */
> >         for (i = 0; i < dc_state->stream_count; i++) {
> >                 struct dc_dsc_policy dsc_policy = {0};
> > @@ -852,11 +848,8 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                 vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> >                 vars[i + k].dsc_enabled = false;
> >                 vars[i + k].bpp_x16 = 0;
> > -               if (drm_dp_atomic_find_time_slots(state,
> > -                                                 params[i].port->mgr,
> > -                                                 params[i].port,
> > -                                                 vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +               if (drm_dp_atomic_find_time_slots(state, params[i].port-
> > > mgr, params[i].port,
> > +                                                 vars[i + k].pbn) < 0)
> >                         return false;
> >         }
> >         if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) {
> > @@ -870,21 +863,15 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                         vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.min_kbps);
> >                         vars[i + k].dsc_enabled = true;
> >                         vars[i + k].bpp_x16 =
> > params[i].bw_range.min_target_bpp_x16;
> > -                       if (drm_dp_atomic_find_time_slots(state,
> > -                                                         params[i].port-
> > >mgr,
> > -                                                         params[i].port,
> > -                                                         vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > params[i].port->mgr,
> > +                                                         params[i].port,
> > vars[i
> > + k].pbn) < 0)
> >                                 return false;
> >                 } else {
> >                         vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> >                         vars[i + k].dsc_enabled = false;
> >                         vars[i + k].bpp_x16 = 0;
> > -                       if (drm_dp_atomic_find_time_slots(state,
> > -                                                         params[i].port-
> > >mgr,
> > -                                                         params[i].port,
> > -                                                         vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > params[i].port->mgr,
> > +                                                         params[i].port,
> > vars[i
> > + k].pbn) < 0)
> >                                 return false;
> >                 }
> >         }
> > @@ -892,7 +879,7 @@ static bool compute_mst_dsc_configs_for_link(struct
> > drm_atomic_state *state,
> >                 return false;
> > 
> >         /* Optimize degree of compression */
> > -       increase_dsc_bpp(state, dc_link, params, vars, count, k);
> > +       increase_dsc_bpp(state, mst_state, dc_link, params, vars, count,
> > k);
> > 
> >         try_disable_dsc(state, dc_link, params, vars, count, k);
> > 
> > @@ -1036,9 +1023,9 @@ bool compute_mst_dsc_configs_for_state(struct
> > drm_atomic_state *state,
> >                         continue;
> > 
> >                 mutex_lock(&aconnector->mst_mgr.lock);
> > -               if (!compute_mst_dsc_configs_for_link(state, dc_state,
> > stream->link,
> > -                       vars, &link_vars_start_index)) {
> > -                       mutex_unlock(&aconnector->mst_mgr.lock);
> > +               if (!compute_mst_dsc_configs_for_link(state, dc_state,
> > stream->link, vars,
> > +                                                     &aconnector-
> > >mst_mgr,
> > +                                                    
> > &link_vars_start_index)) {
> 
> Should still keep "mutex_unlock(&aconnector->mst_mgr.lock);" here.
> 
> >                         return false;
> >                 }
> >                 mutex_unlock(&aconnector->mst_mgr.lock);
> > @@ -1095,10 +1082,8 @@ static bool
> >                         continue;
> > 
> >                 mutex_lock(&aconnector->mst_mgr.lock);
> > -               if (!compute_mst_dsc_configs_for_link(state,
> > -                                                     dc_state,
> > -                                                     stream->link,
> > -                                                     vars,
> > +               if (!compute_mst_dsc_configs_for_link(state, dc_state,
> > stream->link, vars,
> > +                                                     &aconnector-
> > >mst_mgr,
> >                                                      
> > &link_vars_start_index)) {
> >                         mutex_unlock(&aconnector->mst_mgr.lock);
> >                         return false;
> > diff --git a/drivers/gpu/drm/amd/display/include/link_service_types.h
> > b/drivers/gpu/drm/amd/display/include/link_service_types.h
> > index 91bffc5bf52c..143baab54b41 100644
> > --- a/drivers/gpu/drm/amd/display/include/link_service_types.h
> > +++ b/drivers/gpu/drm/amd/display/include/link_service_types.h
> > @@ -250,12 +250,19 @@ union dpcd_training_lane_set {
> >   * _ONLY_ be filled out from DM and then passed to DC, do NOT use these
> > for _any_ kind of atomic
> >   * state calculations in DM, or you will break something.
> >   */
> > +
> > +struct drm_dp_mst_port;
> > +
> >  /* DP MST stream allocation (payload bandwidth number) */
> >  struct dc_dp_mst_stream_allocation {
> >         uint8_t vcp_id;
> >         /* number of slots required for the DP stream in
> >          * transport packet */
> >         uint8_t slot_count;
> > +       /* The MST port this is on, this is used to associate DC MST
> > payloads
> > with their
> > +        * respective DRM payloads allocations, and can be ignored on non-
> > Linux.
> > +        */
> 
> Is it necessary for adding this new member? Since this is for setting the DC
> HW and not relating to drm.
> 
> > +       struct drm_dp_mst_port *port;
> >  };
> > 
> >  /* DP MST stream allocation table */
> > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > index 10d26a7e028c..d8e32269585b 100644
> > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > @@ -67,8 +67,7 @@ static bool dump_dp_payload_table(struct
> > drm_dp_mst_topology_mgr *mgr,
> >  static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port
> > *port);
> > 
> >  static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                    int id,
> > -                                    struct drm_dp_payload *payload);
> > +                                    int id, u8 start_slot, u8 num_slots);
> > 
> >  static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> >                                  struct drm_dp_mst_port *port,
> > @@ -1234,57 +1233,6 @@ build_query_stream_enc_status(struct
> > drm_dp_sideband_msg_tx *msg, u8 stream_id,
> >         return 0;
> >  }
> > 
> > -static int drm_dp_mst_assign_payload_id(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                       struct drm_dp_vcpi *vcpi)
> > -{
> > -       int ret, vcpi_ret;
> > -
> > -       mutex_lock(&mgr->payload_lock);
> > -       ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads
> > + 1);
> > -       if (ret > mgr->max_payloads) {
> > -               ret = -EINVAL;
> > -               drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
> > -               goto out_unlock;
> > -       }
> > -
> > -       vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr-
> > > max_payloads + 1);
> > -       if (vcpi_ret > mgr->max_payloads) {
> > -               ret = -EINVAL;
> > -               drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
> > -               goto out_unlock;
> > -       }
> > -
> > -       set_bit(ret, &mgr->payload_mask);
> > -       set_bit(vcpi_ret, &mgr->vcpi_mask);
> > -       vcpi->vcpi = vcpi_ret + 1;
> > -       mgr->proposed_vcpis[ret - 1] = vcpi;
> > -out_unlock:
> > -       mutex_unlock(&mgr->payload_lock);
> > -       return ret;
> > -}
> > -
> > -static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                     int vcpi)
> > -{
> > -       int i;
> > -
> > -       if (vcpi == 0)
> > -               return;
> > -
> > -       mutex_lock(&mgr->payload_lock);
> > -       drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
> > -       clear_bit(vcpi - 1, &mgr->vcpi_mask);
> > -
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -               if (mgr->proposed_vcpis[i] &&
> > -                   mgr->proposed_vcpis[i]->vcpi == vcpi) {
> > -                       mgr->proposed_vcpis[i] = NULL;
> > -                       clear_bit(i + 1, &mgr->payload_mask);
> > -               }
> > -       }
> > -       mutex_unlock(&mgr->payload_lock);
> > -}
> > -
> >  static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
> >                               struct drm_dp_sideband_msg_tx *txmsg)
> >  {
> > @@ -1737,7 +1685,7 @@ drm_dp_mst_dump_port_topology_history(struct
> > drm_dp_mst_port *port) {}
> >  #define save_port_topology_ref(port, type)
> >  #endif
> > 
> > -static struct drm_dp_mst_atomic_payload *
> > +struct drm_dp_mst_atomic_payload *
> >  drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state
> > *state,
> >                                  struct drm_dp_mst_port *port)
> >  {
> > @@ -1749,6 +1697,7 @@ drm_atomic_get_mst_payload_state(struct
> > drm_dp_mst_topology_state *state,
> > 
> >         return NULL;
> >  }
> > +EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
> > 
> >  static void drm_dp_destroy_mst_branch_device(struct kref *kref)
> >  {
> > @@ -3272,6 +3221,8 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >                 struct drm_dp_mst_port *port,
> >                 struct drm_dp_query_stream_enc_status_ack_reply *status)
> >  {
> > +       struct drm_dp_mst_topology_state *state;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         struct drm_dp_sideband_msg_tx *txmsg;
> >         u8 nonce[7];
> >         int ret;
> > @@ -3288,6 +3239,10 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> > 
> >         get_random_bytes(nonce, sizeof(nonce));
> > 
> > +       drm_modeset_lock(&mgr->base.lock, NULL);
> > +       state = to_drm_dp_mst_topology_state(mgr->base.state);
> > +       payload = drm_atomic_get_mst_payload_state(state, port);
> > +
> >         /*
> >          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS
> > message
> >          *  transaction at the MST Branch device directly connected to the
> > @@ -3295,7 +3250,7 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >          */
> >         txmsg->dst = mgr->mst_primary;
> > 
> > -       build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
> > +       build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
> > 
> >         drm_dp_queue_down_tx(mgr, txmsg);
> > 
> > @@ -3312,6 +3267,7 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
> > 
> >  out:
> > +       drm_modeset_unlock(&mgr->base.lock);
> >         drm_dp_mst_topology_put_port(port);
> >  out_get_port:
> >         kfree(txmsg);
> > @@ -3320,219 +3276,161 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >  EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
> > 
> >  static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                      int id,
> > -                                      struct drm_dp_payload *payload)
> > +                                      struct drm_dp_mst_atomic_payload
> > *payload)
> >  {
> > -       int ret;
> > -
> > -       ret = drm_dp_dpcd_write_payload(mgr, id, payload);
> > -       if (ret < 0) {
> > -               payload->payload_state = 0;
> > -               return ret;
> > -       }
> > -       payload->payload_state = DP_PAYLOAD_LOCAL;
> > -       return 0;
> > +       return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload-
> > > vc_start_slot,
> > +                                        payload->time_slots);
> >  }
> > 
> >  static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                      struct drm_dp_mst_port *port,
> > -                                      int id,
> > -                                      struct drm_dp_payload *payload)
> > +                                      struct drm_dp_mst_atomic_payload
> > *payload)
> >  {
> >         int ret;
> > +       struct drm_dp_mst_port *port =
> > drm_dp_mst_topology_get_port_validated(mgr, payload->port);
> > 
> > -       ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
> > -       if (ret < 0)
> > -               return ret;
> > -       payload->payload_state = DP_PAYLOAD_REMOTE;
> > +       if (!port)
> > +               return -EIO;
> > +
> > +       ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload-
> > > pbn);
> > +       drm_dp_mst_topology_put_port(port);
> >         return ret;
> >  }
> > 
> >  static int drm_dp_destroy_payload_step1(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                       struct drm_dp_mst_port *port,
> > -                                       int id,
> > -                                       struct drm_dp_payload *payload)
> > +                                       struct drm_dp_mst_topology_state
> > *mst_state,
> > +                                       struct drm_dp_mst_atomic_payload
> > *payload)
> >  {
> > +
> >         drm_dbg_kms(mgr->dev, "\n");
> > -       /* it's okay for these to fail */
> > -       if (port) {
> > -               drm_dp_payload_send_msg(mgr, port, id, 0);
> > -       }
> > 
> > -       drm_dp_dpcd_write_payload(mgr, id, payload);
> > -       payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
> > -       return 0;
> > -}
> > +       /* it's okay for these to fail */
> > +       drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
> > +       drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload-
> > > vc_start_slot, 0);
> > 
> > -static int drm_dp_destroy_payload_step2(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                       int id,
> > -                                       struct drm_dp_payload *payload)
> > -{
> > -       payload->payload_state = 0;
> >         return 0;
> >  }
> > 
> >  /**
> > - * drm_dp_update_payload_part1() - Execute payload update part 1
> > - * @mgr: manager to use.
> > - * @start_slot: this is the cur slot
> > + * drm_dp_add_payload_part1() - Execute payload update part 1
> > + * @mgr: Manager to use.
> > + * @mst_state: The MST atomic state
> > + * @payload: The payload to write
> >   *
> > - * NOTE: start_slot is a temporary workaround for non-atomic drivers,
> > - * this will be removed when non-atomic mst helpers are moved out of the
> > helper
> > + * Determines the starting time slot for the given payload, and programs
> > the
> > VCPI for this payload
> > + * into hardware.
> >   *
> > - * This iterates over all proposed virtual channels, and tries to
> > - * allocate space in the link for them. For 0->slots transitions,
> > - * this step just writes the VCPI to the MST device. For slots->0
> > - * transitions, this writes the updated VCPIs and removes the
> > - * remote VC payloads.
> > + * After calling this, the driver should generate ACT and payload
> > packets.
> > Note that the driver may
> > + * generate ACT once per payload change, or only once after all new
> > payloads in a given atomic state
> > + * have been added.
> >   *
> > - * after calling this the driver should generate ACT and payload
> > - * packets.
> > + * Returns: 0 on success, error code on failure. In the event that this
> > fails,
> > + * @payload.vc_start_slot will also be set to -1.
> >   */
> > -int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr
> > *mgr, int start_slot)
> > +int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_dp_mst_topology_state *mst_state,
> > +                            struct drm_dp_mst_atomic_payload *payload)
> >  {
> > -       struct drm_dp_payload req_payload;
> >         struct drm_dp_mst_port *port;
> > -       int i, j;
> > -       int cur_slots = start_slot;
> > -
> > -       mutex_lock(&mgr->payload_lock);
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -               struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> > -               struct drm_dp_payload *payload = &mgr->payloads[i];
> > -               bool put_port = false;
> > -
> > -               /* solve the current payloads - compare to the hw ones
> > -                  - update the hw view */
> > -               req_payload.start_slot = cur_slots;
> > -               if (vcpi) {
> > -                       port = container_of(vcpi, struct drm_dp_mst_port,
> > -                                           vcpi);
> > -
> > -                       /* Validated ports don't matter if we're releasing
> > -                        * VCPI
> > -                        */
> > -                       if (vcpi->num_slots) {
> > -                               port =
> > drm_dp_mst_topology_get_port_validated(
> > -                                   mgr, port);
> > -                               if (!port) {
> > -                                       if (vcpi->num_slots == payload-
> > > num_slots) {
> > -                                               cur_slots += vcpi-
> > >num_slots;
> > -                                               payload->start_slot =
> > req_payload.start_slot;
> > -                                               continue;
> > -                                       } else {
> > -                                               drm_dbg_kms(mgr->dev,
> > -                                                           "Fail:set
> > payload to
> > invalid sink");
> > -                                               mutex_unlock(&mgr-
> > > payload_lock);
> > -                                               return -EINVAL;
> > -                                       }
> > -                               }
> > -                               put_port = true;
> > -                       }
> > +       int ret;
> > 
> > -                       req_payload.num_slots = vcpi->num_slots;
> > -                       req_payload.vcpi = vcpi->vcpi;
> > -               } else {
> > -                       port = NULL;
> > -                       req_payload.num_slots = 0;
> > -               }
> > +       port = drm_dp_mst_topology_get_port_validated(mgr, payload-
> > > port);
> > +       if (!port)
> > +               return 0;
> > 
> > -               payload->start_slot = req_payload.start_slot;
> > -               /* work out what is required to happen with this payload
> > */
> > -               if (payload->num_slots != req_payload.num_slots) {
> > -
> > -                       /* need to push an update for this payload */
> > -                       if (req_payload.num_slots) {
> > -                               drm_dp_create_payload_step1(mgr, vcpi-
> > > vcpi,
> > -                                                           &req_payload);
> > -                               payload->num_slots =
> > req_payload.num_slots;
> > -                               payload->vcpi = req_payload.vcpi;
> > -
> > -                       } else if (payload->num_slots) {
> > -                               payload->num_slots = 0;
> > -                               drm_dp_destroy_payload_step1(mgr, port,
> > -                                                            payload-
> > >vcpi,
> > -                                                            payload);
> > -                               req_payload.payload_state =
> > -                                       payload->payload_state;
> > -                               payload->start_slot = 0;
> > -                       }
> > -                       payload->payload_state =
> > req_payload.payload_state;
> > -               }
> > -               cur_slots += req_payload.num_slots;
> > +       if (mgr->payload_count == 0)
> > +               mgr->next_start_slot = mst_state->start_slot;
> > 
> > -               if (put_port)
> > -                       drm_dp_mst_topology_put_port(port);
> > +       payload->vc_start_slot = mgr->next_start_slot;
> > +       ret = drm_dp_create_payload_step1(mgr, payload);
> > +       drm_dp_mst_topology_put_port(port);
> > +       if (ret < 0) {
> > +               drm_warn(mgr->dev, "Failed to create MST payload for port
> > %p: %d\n",
> > +                        payload->port, ret);
> > +               payload->vc_start_slot = -1;
> > +               return ret;
> >         }
> > 
> > -       for (i = 0; i < mgr->max_payloads; /* do nothing */) {
> > -               if (mgr->payloads[i].payload_state !=
> > DP_PAYLOAD_DELETE_LOCAL) {
> > -                       i++;
> > -                       continue;
> > -               }
> > +       mgr->payload_count++;
> > +       mgr->next_start_slot += payload->time_slots;
> > 
> > -               drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
> > -               for (j = i; j < mgr->max_payloads - 1; j++) {
> > -                       mgr->payloads[j] = mgr->payloads[j + 1];
> > -                       mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j +
> > 1];
> > +       return 0;
> > +}
> > +EXPORT_SYMBOL(drm_dp_add_payload_part1);
> > 
> > -                       if (mgr->proposed_vcpis[j] &&
> > -                           mgr->proposed_vcpis[j]->num_slots) {
> > -                               set_bit(j + 1, &mgr->payload_mask);
> > -                       } else {
> > -                               clear_bit(j + 1, &mgr->payload_mask);
> > -                       }
> > -               }
> > +/**
> > + * drm_dp_remove_payload() - Remove an MST payload
> > + * @mgr: Manager to use.
> > + * @mst_state: The MST atomic state
> > + * @payload: The payload to write
> > + *
> > + * Removes a payload from an MST topology if it was successfully assigned
> > a
> > start slot. Also updates
> > + * the starting time slots of all other payloads which would have been
> > shifted towards the start of
> > + * the VC table as a result.
> > + *
> > + * After calling this, the driver should generate ACT and payload
> > packets.
> > Note that the driver may
> > + * generate ACT once per payload change, or only once after all payloads
> > for
> > a given atomic state
> > + * have been removed.
> > + */
> > +void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
> > +                          struct drm_dp_mst_topology_state *mst_state,
> > +                          struct drm_dp_mst_atomic_payload *payload)
> > +{
> > +       struct drm_dp_mst_atomic_payload *pos;
> > 
> > -               memset(&mgr->payloads[mgr->max_payloads - 1], 0,
> > -                      sizeof(struct drm_dp_payload));
> > -               mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
> > -               clear_bit(mgr->max_payloads, &mgr->payload_mask);
> > +       /* We failed to make the payload, so nothing to do */
> > +       if (payload->vc_start_slot == -1)
> > +               return;
> > +
> > +       drm_dp_destroy_payload_step1(mgr, mst_state, payload);
> > +
> > +       list_for_each_entry(pos, &mst_state->payloads, next) {
> > +               if (pos != payload && pos->vc_start_slot > payload-
> > > vc_start_slot)
> > +                       pos->vc_start_slot -= payload->time_slots;
> >         }
> > -       mutex_unlock(&mgr->payload_lock);
> > +       payload->vc_start_slot = -1;
> > 
> > -       return 0;
> > +       mgr->payload_count--;
> > +       mgr->next_start_slot -= payload->time_slots;
> >  }
> > -EXPORT_SYMBOL(drm_dp_update_payload_part1);
> > +EXPORT_SYMBOL(drm_dp_remove_payload);
> > 
> >  /**
> > - * drm_dp_update_payload_part2() - Execute payload update part 2
> > - * @mgr: manager to use.
> > + * drm_dp_add_payload_part2() - Execute payload update part 2
> > + * @mgr: Manager to use.
> > + * @state: The global atomic state
> > + * @payload: The payload to update
> > + *
> > + * If @payload was successfully assigned a starting time slot by
> > drm_dp_add_payload_part1(), this
> > + * function will send the sideband messages to finish allocating this
> > payload.
> >   *
> > - * This iterates over all proposed virtual channels, and tries to
> > - * allocate space in the link for them. For 0->slots transitions,
> > - * this step writes the remote VC payload commands. For slots->0
> > - * this just resets some internal state.
> > + * Returns: 0 on success, negative error code on failure.
> >   */
> > -int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr
> > *mgr)
> > +int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_atomic_state *state,
> > +                            struct drm_dp_mst_atomic_payload *payload)
> >  {
> > -       struct drm_dp_mst_port *port;
> > -       int i;
> >         int ret = 0;
> > 
> > -       mutex_lock(&mgr->payload_lock);
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -
> > -               if (!mgr->proposed_vcpis[i])
> > -                       continue;
> > -
> > -               port = container_of(mgr->proposed_vcpis[i], struct
> > drm_dp_mst_port, vcpi);
> > +       /* Skip failed payloads */
> > +       if (payload->vc_start_slot == -1) {
> > +               drm_dbg_kms(state->dev, "Part 1 of payload creation for %s
> > failed, skipping part 2\n",
> > +                           payload->port->connector->name);
> > +               return -EIO;
> > +       }
> > 
> > -               drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr-
> > > payloads[i].payload_state);
> > -               if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL)
> > {
> > -                       ret = drm_dp_create_payload_step2(mgr, port, mgr-
> > > proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
> > -               } else if (mgr->payloads[i].payload_state ==
> > DP_PAYLOAD_DELETE_LOCAL) {
> > -                       ret = drm_dp_destroy_payload_step2(mgr, mgr-
> > > proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
> > -               }
> > -               if (ret) {
> > -                       mutex_unlock(&mgr->payload_lock);
> > -                       return ret;
> > -               }
> > +       ret = drm_dp_create_payload_step2(mgr, payload);
> > +       if (ret < 0) {
> > +               if (!payload->delete)
> > +                       drm_err(mgr->dev, "Step 2 of creating MST payload
> > for %p failed: %d\n",
> > +                               payload->port, ret);
> > +               else
> > +                       drm_dbg_kms(mgr->dev, "Step 2 of removing MST
> > payload for %p failed: %d\n",
> > +                                   payload->port, ret);
> >         }
> > -       mutex_unlock(&mgr->payload_lock);
> > -       return 0;
> > +
> > +       return ret;
> >  }
> > -EXPORT_SYMBOL(drm_dp_update_payload_part2);
> > +EXPORT_SYMBOL(drm_dp_add_payload_part2);
> > 
> >  static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> >                                  struct drm_dp_mst_port *port,
> > @@ -3712,7 +3610,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >         int ret = 0;
> >         struct drm_dp_mst_branch *mstb = NULL;
> > 
> > -       mutex_lock(&mgr->payload_lock);
> >         mutex_lock(&mgr->lock);
> >         if (mst_state == mgr->mst_state)
> >                 goto out_unlock;
> > @@ -3720,10 +3617,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >         mgr->mst_state = mst_state;
> >         /* set the device into MST mode */
> >         if (mst_state) {
> > -               struct drm_dp_payload reset_pay;
> > -               int lane_count;
> > -               int link_rate;
> > -
> >                 WARN_ON(mgr->mst_primary);
> > 
> >                 /* get dpcd info */
> > @@ -3734,16 +3627,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >                         goto out_unlock;
> >                 }
> > 
> > -               lane_count = min_t(int, mgr->dpcd[2] &
> > DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
> > -               link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr-
> > > dpcd[1]), mgr->max_link_rate);
> > -               mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
> > -                                                       link_rate,
> > -                                                       lane_count);
> > -               if (mgr->pbn_div == 0) {
> > -                       ret = -EINVAL;
> > -                       goto out_unlock;
> > -               }
> > -
> >                 /* add initial branch device at LCT 1 */
> >                 mstb = drm_dp_add_mst_branch_device(1, NULL);
> >                 if (mstb == NULL) {
> > @@ -3763,9 +3646,8 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >                 if (ret < 0)
> >                         goto out_unlock;
> > 
> > -               reset_pay.start_slot = 0;
> > -               reset_pay.num_slots = 0x3f;
> > -               drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
> > +               /* Write reset payload */
> > +               drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
> > 
> >                 queue_work(system_long_wq, &mgr->work);
> > 
> > @@ -3777,19 +3659,11 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >                 /* this can fail if the device is gone */
> >                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
> >                 ret = 0;
> > -               memset(mgr->payloads, 0,
> > -                      mgr->max_payloads * sizeof(mgr->payloads[0]));
> > -               memset(mgr->proposed_vcpis, 0,
> > -                      mgr->max_payloads * sizeof(mgr-
> > >proposed_vcpis[0]));
> > -               mgr->payload_mask = 0;
> > -               set_bit(0, &mgr->payload_mask);
> > -               mgr->vcpi_mask = 0;
> >                 mgr->payload_id_table_cleared = false;
> >         }
> > 
> >  out_unlock:
> >         mutex_unlock(&mgr->lock);
> > -       mutex_unlock(&mgr->payload_lock);
> >         if (mstb)
> >                 drm_dp_mst_topology_put_mstb(mstb);
> >         return ret;
> > @@ -4310,62 +4184,18 @@ struct edid *drm_dp_mst_get_edid(struct
> > drm_connector *connector, struct drm_dp_
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_get_edid);
> > 
> > -/**
> > - * drm_dp_find_vcpi_slots() - Find time slots for this PBN value
> > - * @mgr: manager to use
> > - * @pbn: payload bandwidth to convert into slots.
> > - *
> > - * Calculate the number of time slots that will be required for the given
> > PBN
> > - * value. This function is deprecated, and should not be used in atomic
> > - * drivers.
> > - *
> > - * RETURNS:
> > - * The total slots required for this port, or error.
> > - */
> > -int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > -                          int pbn)
> > -{
> > -       int num_slots;
> > -
> > -       num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
> > -
> > -       /* max. time slots - one slot for MTP header */
> > -       if (num_slots > 63)
> > -               return -ENOSPC;
> > -       return num_slots;
> > -}
> > -EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
> > -
> > -static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                           struct drm_dp_vcpi *vcpi, int pbn, int slots)
> > -{
> > -       int ret;
> > -
> > -       vcpi->pbn = pbn;
> > -       vcpi->aligned_pbn = slots * mgr->pbn_div;
> > -       vcpi->num_slots = slots;
> > -
> > -       ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
> > -       if (ret < 0)
> > -               return ret;
> > -       return 0;
> > -}
> > -
> >  /**
> >   * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
> >   * @state: global atomic state
> >   * @mgr: MST topology manager for the port
> >   * @port: port to find time slots for
> >   * @pbn: bandwidth required for the mode in PBN
> > - * @pbn_div: divider for DSC mode that takes FEC into account
> >   *
> > - * Allocates time slots to @port, replacing any previous timeslot
> > allocations it
> > - * may have had. Any atomic drivers which support MST must call this
> > function
> > - * in their &drm_encoder_helper_funcs.atomic_check() callback to change
> > the
> > - * current timeslot allocation for the new state, but only when
> > - * &drm_crtc_state.mode_changed or
> > &drm_crtc_state.connectors_changed is set
> > - * to ensure compatibility with userspace applications that still use the
> > - * legacy modesetting UAPI.
> > + * Allocates time slots to @port, replacing any previous time slot
> > allocations
> > it may
> > + * have had. Any atomic drivers which support MST must call this function
> > in
> > + * their &drm_encoder_helper_funcs.atomic_check() callback
> > unconditionally to
> > + * change the current time slot allocation for the new state, and ensure
> > the
> > MST
> > + * atomic state is added whenever the state of payloads in the topology
> > changes.
> >   *
> >   * Allocations set by this function are not checked against the bandwidth
> >   * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
> > @@ -4384,8 +4214,7 @@ static int drm_dp_init_vcpi(struct
> > drm_dp_mst_topology_mgr *mgr,
> >   */
> >  int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> >                                   struct drm_dp_mst_topology_mgr *mgr,
> > -                                 struct drm_dp_mst_port *port, int pbn,
> > -                                 int pbn_div)
> > +                                 struct drm_dp_mst_port *port, int pbn)
> >  {
> >         struct drm_dp_mst_topology_state *topology_state;
> >         struct drm_dp_mst_atomic_payload *payload = NULL;
> > @@ -4418,10 +4247,7 @@ int drm_dp_atomic_find_time_slots(struct
> > drm_atomic_state *state,
> >                 }
> >         }
> > 
> > -       if (pbn_div <= 0)
> > -               pbn_div = mgr->pbn_div;
> > -
> > -       req_slots = DIV_ROUND_UP(pbn, pbn_div);
> > +       req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div);
> > 
> >         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p]
> > TU %d -> %d\n",
> >                        port->connector->base.id, port->connector->name,
> > @@ -4430,7 +4256,7 @@ int drm_dp_atomic_find_time_slots(struct
> > drm_atomic_state *state,
> >                        port->connector->base.id, port->connector->name,
> >                        port, prev_bw, pbn);
> > 
> > -       /* Add the new allocation to the state */
> > +       /* Add the new allocation to the state, note the VCPI isn't
> > assigned
> > until the end */
> >         if (!payload) {
> >                 payload = kzalloc(sizeof(*payload), GFP_KERNEL);
> >                 if (!payload)
> > @@ -4438,6 +4264,7 @@ int drm_dp_atomic_find_time_slots(struct
> > drm_atomic_state *state,
> > 
> >                 drm_dp_mst_get_port_malloc(port);
> >                 payload->port = port;
> > +               payload->vc_start_slot = -1;
> >                 list_add(&payload->next, &topology_state->payloads);
> >         }
> >         payload->time_slots = req_slots;
> > @@ -4454,10 +4281,12 @@
> > EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
> >   * @port: The port to release the time slots from
> >   *
> >   * Releases any time slots that have been allocated to a port in the
> > atomic
> > - * state. Any atomic drivers which support MST must call this function in
> > - * their &drm_connector_helper_funcs.atomic_check() callback when the
> > - * connector will no longer have VCPI allocated (e.g. because its CRTC
> > was
> > - * removed) when it had VCPI allocated in the previous atomic state.
> > + * state. Any atomic drivers which support MST must call this function
> > + * unconditionally in their &drm_connector_helper_funcs.atomic_check()
> > callback.
> > + * This helper will check whether time slots would be released by the new
> > state and
> > + * respond accordingly, along with ensuring the MST state is always added
> > to the
> > + * atomic state whenever a new state would modify the state of payloads
> > on the
> > + * topology.
> >   *
> >   * It is OK to call this even if @port has been removed from the system.
> >   * Additionally, it is OK to call this function multiple times on the
> > same
> > @@ -4519,6 +4348,7 @@ int drm_dp_atomic_release_time_slots(struct
> > drm_atomic_state *state,
> >                 drm_dp_mst_put_port_malloc(port);
> >                 payload->pbn = 0;
> >                 payload->delete = true;
> > +               topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
> >         }
> > 
> >         return 0;
> > @@ -4569,7 +4399,8 @@ int drm_dp_mst_atomic_setup_commit(struct
> > drm_atomic_state *state)
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
> > 
> >  /**
> > - * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending
> > commits on MST topologies
> > + * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending
> > commits on MST topologies,
> > + * prepare new MST state for commit
> >   * @state: global atomic state
> >   *
> >   * Goes through any MST topologies in this atomic state, and waits for
> > any
> > pending commits which
> > @@ -4587,17 +4418,30 @@
> > EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
> >   */
> >  void drm_dp_mst_atomic_wait_for_dependencies(struct
> > drm_atomic_state *state)
> >  {
> > -       struct drm_dp_mst_topology_state *old_mst_state;
> > +       struct drm_dp_mst_topology_state *old_mst_state,
> > *new_mst_state;
> >         struct drm_dp_mst_topology_mgr *mgr;
> > +       struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
> >         int i, j, ret;
> > 
> > -       for_each_old_mst_mgr_in_state(state, mgr, old_mst_state, i) {
> > +       for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state,
> > new_mst_state, i) {
> >                 for (j = 0; j < old_mst_state->num_commit_deps; j++) {
> >                         ret = drm_crtc_commit_wait(old_mst_state-
> > > commit_deps[j]);
> >                         if (ret < 0)
> >                                 drm_err(state->dev, "Failed to wait for
> > %s:
> > %d\n",
> >                                         old_mst_state->commit_deps[j]-
> > > crtc->name, ret);
> >                 }
> > +
> > +               /* Now that previous state is committed, it's safe to copy
> > over the start slot
> > +                * assignments
> > +                */
> > +               list_for_each_entry(old_payload, &old_mst_state->payloads,
> > next) {
> > +                       if (old_payload->delete)
> > +                               continue;
> > +
> > +                       new_payload =
> > drm_atomic_get_mst_payload_state(new_mst_state,
> > +
> > old_payload->port);
> > +                       new_payload->vc_start_slot = old_payload-
> > > vc_start_slot;
> > +               }
> >         }
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
> > @@ -4682,110 +4526,8 @@ void drm_dp_mst_update_slots(struct
> > drm_dp_mst_topology_state *mst_state, uint8_
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_update_slots);
> > 
> > -/**
> > - * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
> > - * @mgr: manager for this port
> > - * @port: port to allocate a virtual channel for.
> > - * @pbn: payload bandwidth number to request
> > - * @slots: returned number of slots for this PBN.
> > - */
> > -bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                             struct drm_dp_mst_port *port, int pbn, int
> > slots)
> > -{
> > -       int ret;
> > -
> > -       if (slots < 0)
> > -               return false;
> > -
> > -       port = drm_dp_mst_topology_get_port_validated(mgr, port);
> > -       if (!port)
> > -               return false;
> > -
> > -       if (port->vcpi.vcpi > 0) {
> > -               drm_dbg_kms(mgr->dev,
> > -                           "payload: vcpi %d already allocated for pbn %d
> > -
> > requested pbn %d\n",
> > -                           port->vcpi.vcpi, port->vcpi.pbn, pbn);
> > -               if (pbn == port->vcpi.pbn) {
> > -                       drm_dp_mst_topology_put_port(port);
> > -                       return true;
> > -               }
> > -       }
> > -
> > -       ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
> > -       if (ret) {
> > -               drm_dbg_kms(mgr->dev, "failed to init time slots=%d
> > ret=%d\n",
> > -                           DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
> > -               drm_dp_mst_topology_put_port(port);
> > -               goto out;
> > -       }
> > -       drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn,
> > port->vcpi.num_slots);
> > -
> > -       /* Keep port allocated until its payload has been removed */
> > -       drm_dp_mst_get_port_malloc(port);
> > -       drm_dp_mst_topology_put_port(port);
> > -       return true;
> > -out:
> > -       return false;
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
> > -
> > -int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > struct drm_dp_mst_port *port)
> > -{
> > -       int slots = 0;
> > -
> > -       port = drm_dp_mst_topology_get_port_validated(mgr, port);
> > -       if (!port)
> > -               return slots;
> > -
> > -       slots = port->vcpi.num_slots;
> > -       drm_dp_mst_topology_put_port(port);
> > -       return slots;
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
> > -
> > -/**
> > - * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
> > - * @mgr: manager for this port
> > - * @port: unverified pointer to a port.
> > - *
> > - * This just resets the number of slots for the ports VCPI for later
> > programming.
> > - */
> > -void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr
> > *mgr, struct drm_dp_mst_port *port)
> > -{
> > -       /*
> > -        * A port with VCPI will remain allocated until its VCPI is
> > -        * released, no verified ref needed
> > -        */
> > -
> > -       port->vcpi.num_slots = 0;
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
> > -
> > -/**
> > - * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
> > - * @mgr: manager for this port
> > - * @port: port to deallocate vcpi for
> > - *
> > - * This can be called unconditionally, regardless of whether
> > - * drm_dp_mst_allocate_vcpi() succeeded or not.
> > - */
> > -void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                               struct drm_dp_mst_port *port)
> > -{
> > -       if (!port->vcpi.vcpi)
> > -               return;
> > -
> > -       drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
> > -       port->vcpi.num_slots = 0;
> > -       port->vcpi.pbn = 0;
> > -       port->vcpi.aligned_pbn = 0;
> > -       port->vcpi.vcpi = 0;
> > -       drm_dp_mst_put_port_malloc(port);
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
> > -
> >  static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                    int id, struct drm_dp_payload
> > *payload)
> > +                                    int id, u8 start_slot, u8 num_slots)
> >  {
> >         u8 payload_alloc[3], status;
> >         int ret;
> > @@ -4795,8 +4537,8 @@ static int drm_dp_dpcd_write_payload(struct
> > drm_dp_mst_topology_mgr *mgr,
> >                            DP_PAYLOAD_TABLE_UPDATED);
> > 
> >         payload_alloc[0] = id;
> > -       payload_alloc[1] = payload->start_slot;
> > -       payload_alloc[2] = payload->num_slots;
> > +       payload_alloc[1] = start_slot;
> > +       payload_alloc[2] = num_slots;
> > 
> >         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET,
> > payload_alloc, 3);
> >         if (ret != 3) {
> > @@ -5011,8 +4753,9 @@ static void fetch_monitor_name(struct
> > drm_dp_mst_topology_mgr *mgr,
> >  void drm_dp_mst_dump_topology(struct seq_file *m,
> >                               struct drm_dp_mst_topology_mgr *mgr)
> >  {
> > -       int i;
> > -       struct drm_dp_mst_port *port;
> > +       struct drm_dp_mst_topology_state *state;
> > +       struct drm_dp_mst_atomic_payload *payload;
> > +       int i, ret;
> > 
> >         mutex_lock(&mgr->lock);
> >         if (mgr->mst_primary)
> > @@ -5021,36 +4764,35 @@ void drm_dp_mst_dump_topology(struct
> > seq_file *m,
> >         /* dump VCPIs */
> >         mutex_unlock(&mgr->lock);
> > 
> > -       mutex_lock(&mgr->payload_lock);
> > -       seq_printf(m, "\n*** VCPI Info ***\n");
> > -       seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads:
> > %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
> > +       ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
> > +       if (ret < 0)
> > +               return;
> > +
> > +       state = to_drm_dp_mst_topology_state(mgr->base.state);
> > +       seq_printf(m, "\n*** Atomic state info ***\n");
> > +       seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u,
> > pbn_div: %d\n",
> > +                  state->payload_mask, mgr->max_payloads, state-
> > > start_slot, state->pbn_div);
> > 
> > -       seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |    
> > sink name
> > > \n");
> > +       seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc |    
> > sink name
> > > \n");
> >         for (i = 0; i < mgr->max_payloads; i++) {
> > -               if (mgr->proposed_vcpis[i]) {
> > +               list_for_each_entry(payload, &state->payloads, next) {
> >                         char name[14];
> > 
> > -                       port = container_of(mgr->proposed_vcpis[i], struct
> > drm_dp_mst_port, vcpi);
> > -                       fetch_monitor_name(mgr, port, name,
> > sizeof(name));
> > -                       seq_printf(m, "%10d%10d%10d%10d%20s\n",
> > +                       if (payload->vcpi != i || payload->delete)
> > +                               continue;
> > +
> > +                       fetch_monitor_name(mgr, payload->port, name,
> > sizeof(name));
> > +                       seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s
> > %19s\n",
> >                                    i,
> > -                                  port->port_num,
> > -                                  port->vcpi.vcpi,
> > -                                  port->vcpi.num_slots,
> > +                                  payload->port->port_num,
> > +                                  payload->vcpi,
> > +                                  payload->vc_start_slot,
> > +                                  payload->vc_start_slot + payload-
> > > time_slots - 1,
> > +                                  payload->pbn,
> > +                                  payload->dsc_enabled ? "Y" : "N",
> >                                    (*name != 0) ? name : "Unknown");
> > -               } else
> > -                       seq_printf(m, "%6d - Unused\n", i);
> > -       }
> > -       seq_printf(m, "\n*** Payload Info ***\n");
> > -       seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -               seq_printf(m, "%10d%10d%15d%10d\n",
> > -                          i,
> > -                          mgr->payloads[i].payload_state,
> > -                          mgr->payloads[i].start_slot,
> > -                          mgr->payloads[i].num_slots);
> > +               }
> >         }
> > -       mutex_unlock(&mgr->payload_lock);
> > 
> >         seq_printf(m, "\n*** DPCD Info ***\n");
> >         mutex_lock(&mgr->lock);
> > @@ -5097,7 +4839,7 @@ void drm_dp_mst_dump_topology(struct seq_file
> > *m,
> > 
> >  out:
> >         mutex_unlock(&mgr->lock);
> > -
> > +       drm_modeset_unlock(&mgr->base.lock);
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_dump_topology);
> > 
> > @@ -5418,9 +5160,22 @@
> > drm_dp_mst_atomic_check_payload_alloc_limits(struct
> > drm_dp_mst_topology_mgr *mgr
> >                                        mgr, mst_state, mgr->max_payloads);
> >                         return -EINVAL;
> >                 }
> > +
> > +               /* Assign a VCPI */
> > +               if (!payload->vcpi) {
> > +                       payload->vcpi = ffz(mst_state->payload_mask) + 1;
> > +                       drm_dbg_atomic(mgr->dev, "[MST PORT:%p]
> > assigned VCPI #%d\n",
> > +                                      payload->port, payload->vcpi);
> > +                       mst_state->payload_mask |= BIT(payload->vcpi - 1);
> > +               }
> >         }
> > -       drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU
> > avail=%d used=%d\n",
> > -                      mgr, mst_state, avail_slots, mst_state-
> > >total_avail_slots -
> > avail_slots);
> > +
> > +       if (!payload_count)
> > +               mst_state->pbn_div = 0;
> > +
> > +       drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU
> > pbn_div=%d avail=%d used=%d\n",
> > +                      mgr, mst_state, mst_state->pbn_div, avail_slots,
> > +                      mst_state->total_avail_slots - avail_slots);
> > 
> >         return 0;
> >  }
> > @@ -5491,7 +5246,6 @@
> > EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
> >   * @state: Pointer to the new drm_atomic_state
> >   * @port: Pointer to the affected MST Port
> >   * @pbn: Newly recalculated bw required for link with DSC enabled
> > - * @pbn_div: Divider to calculate correct number of pbn per slot
> >   * @enable: Boolean flag to enable or disable DSC on the port
> >   *
> >   * This function enables DSC on the given Port
> > @@ -5502,8 +5256,7 @@
> > EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
> >   */
> >  int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
> >                                  struct drm_dp_mst_port *port,
> > -                                int pbn, int pbn_div,
> > -                                bool enable)
> > +                                int pbn, bool enable)
> >  {
> >         struct drm_dp_mst_topology_state *mst_state;
> >         struct drm_dp_mst_atomic_payload *payload;
> > @@ -5529,7 +5282,7 @@ int drm_dp_mst_atomic_enable_dsc(struct
> > drm_atomic_state *state,
> >         }
> > 
> >         if (enable) {
> > -               time_slots = drm_dp_atomic_find_time_slots(state, port-
> > > mgr, port, pbn, pbn_div);
> > +               time_slots = drm_dp_atomic_find_time_slots(state, port-
> > > mgr, port, pbn);
> >                 drm_dbg_atomic(state->dev,
> >                                "[MST PORT:%p] Enabling DSC flag,
> > reallocating
> > %d time slots on the port\n",
> >                                port, time_slots);
> > @@ -5542,6 +5295,7 @@ int drm_dp_mst_atomic_enable_dsc(struct
> > drm_atomic_state *state,
> >         return time_slots;
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
> > +
> >  /**
> >   * drm_dp_mst_atomic_check - Check that the new state of an MST
> > topology in an
> >   * atomic update is valid
> > @@ -5599,7 +5353,6 @@
> > EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
> > 
> >  /**
> >   * drm_atomic_get_mst_topology_state: get MST topology state
> > - *
> >   * @state: global atomic state
> >   * @mgr: MST topology manager, also the private object in this case
> >   *
> > @@ -5619,6 +5372,31 @@ struct drm_dp_mst_topology_state
> > *drm_atomic_get_mst_topology_state(struct drm_a
> >  }
> >  EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> > 
> > +/**
> > + * drm_atomic_get_new_mst_topology_state: get new MST topology state
> > in atomic state, if any
> > + * @state: global atomic state
> > + * @mgr: MST topology manager, also the private object in this case
> > + *
> > + * This function wraps drm_atomic_get_priv_obj_state() passing in the MST
> > atomic
> > + * state vtable so that the private object state returned is that of a
> > MST
> > + * topology object.
> > + *
> > + * Returns:
> > + *
> > + * The MST topology state, or NULL if there's no topology state for this
> > MST
> > mgr
> > + * in the global atomic state
> > + */
> > +struct drm_dp_mst_topology_state *
> > +drm_atomic_get_new_mst_topology_state(struct drm_atomic_state
> > *state,
> > +                                     struct drm_dp_mst_topology_mgr *mgr)
> > +{
> > +       struct drm_private_state *priv_state =
> > +               drm_atomic_get_new_private_obj_state(state, &mgr-
> > > base);
> > +
> > +       return priv_state ? to_dp_mst_topology_state(priv_state) : NULL;
> > +}
> > +EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
> > +
> >  /**
> >   * drm_dp_mst_topology_mgr_init - initialise a topology manager
> >   * @mgr: manager struct to initialise
> > @@ -5626,8 +5404,6 @@
> > EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> >   * @aux: DP helper aux channel to talk to this device
> >   * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
> >   * @max_payloads: maximum number of payloads this GPU can source
> > - * @max_lane_count: maximum number of lanes this GPU supports
> > - * @max_link_rate: maximum link rate per lane this GPU supports in kHz
> >   * @conn_base_id: the connector object ID the MST device is connected to.
> >   *
> >   * Return 0 for success, or negative error code on failure
> > @@ -5635,14 +5411,12 @@
> > EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> >  int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr
> > *mgr,
> >                                  struct drm_device *dev, struct drm_dp_aux
> > *aux,
> >                                  int max_dpcd_transaction_bytes, int
> > max_payloads,
> > -                                int max_lane_count, int max_link_rate,
> >                                  int conn_base_id)
> >  {
> >         struct drm_dp_mst_topology_state *mst_state;
> > 
> >         mutex_init(&mgr->lock);
> >         mutex_init(&mgr->qlock);
> > -       mutex_init(&mgr->payload_lock);
> >         mutex_init(&mgr->delayed_destroy_lock);
> >         mutex_init(&mgr->up_req_lock);
> >         mutex_init(&mgr->probe_lock);
> > @@ -5672,19 +5446,7 @@ int drm_dp_mst_topology_mgr_init(struct
> > drm_dp_mst_topology_mgr *mgr,
> >         mgr->aux = aux;
> >         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
> >         mgr->max_payloads = max_payloads;
> > -       mgr->max_lane_count = max_lane_count;
> > -       mgr->max_link_rate = max_link_rate;
> >         mgr->conn_base_id = conn_base_id;
> > -       if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
> > -           max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
> > -               return -EINVAL;
> > -       mgr->payloads = kcalloc(max_payloads, sizeof(struct
> > drm_dp_payload), GFP_KERNEL);
> > -       if (!mgr->payloads)
> > -               return -ENOMEM;
> > -       mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct
> > drm_dp_vcpi *), GFP_KERNEL);
> > -       if (!mgr->proposed_vcpis)
> > -               return -ENOMEM;
> > -       set_bit(0, &mgr->payload_mask);
> > 
> >         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
> >         if (mst_state == NULL)
> > @@ -5717,19 +5479,12 @@ void drm_dp_mst_topology_mgr_destroy(struct
> > drm_dp_mst_topology_mgr *mgr)
> >                 destroy_workqueue(mgr->delayed_destroy_wq);
> >                 mgr->delayed_destroy_wq = NULL;
> >         }
> > -       mutex_lock(&mgr->payload_lock);
> > -       kfree(mgr->payloads);
> > -       mgr->payloads = NULL;
> > -       kfree(mgr->proposed_vcpis);
> > -       mgr->proposed_vcpis = NULL;
> > -       mutex_unlock(&mgr->payload_lock);
> >         mgr->dev = NULL;
> >         mgr->aux = NULL;
> >         drm_atomic_private_obj_fini(&mgr->base);
> >         mgr->funcs = NULL;
> > 
> >         mutex_destroy(&mgr->delayed_destroy_lock);
> > -       mutex_destroy(&mgr->payload_lock);
> >         mutex_destroy(&mgr->qlock);
> >         mutex_destroy(&mgr->lock);
> >         mutex_destroy(&mgr->up_req_lock);
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 4b0af3c26176..ec389e3caf24 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -52,6 +52,7 @@ static int intel_dp_mst_compute_link_config(struct
> > intel_encoder *encoder,
> >         struct drm_atomic_state *state = crtc_state->uapi.state;
> >         struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> >         struct intel_dp *intel_dp = &intel_mst->primary->dp;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct intel_connector *connector =
> >                 to_intel_connector(conn_state->connector);
> >         struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > @@ -60,22 +61,28 @@ static int intel_dp_mst_compute_link_config(struct
> > intel_encoder *encoder,
> >         bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> > DP_DPCD_QUIRK_CONSTANT_N);
> >         int bpp, slots = -EINVAL;
> > 
> > +       mst_state = drm_atomic_get_mst_topology_state(state, &intel_dp-
> > > mst_mgr);
> > +       if (IS_ERR(mst_state))
> > +               return PTR_ERR(mst_state);
> > +
> >         crtc_state->lane_count = limits->max_lane_count;
> >         crtc_state->port_clock = limits->max_rate;
> > 
> > +       // TODO: Handle pbn_div changes by adding a new MST helper
> > +       if (!mst_state->pbn_div) {
> > +               mst_state->pbn_div =
> > drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
> > +                                                             limits-
> > >max_rate,
> > +                                                             limits-
> > > max_lane_count);
> > +       }
> > +
> >         for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3)
> > {
> >                 crtc_state->pipe_bpp = bpp;
> > 
> >                 crtc_state->pbn =
> > drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
> >                                                        crtc_state-
> > >pipe_bpp,
> >                                                        false);
> > -
> >                 slots = drm_dp_atomic_find_time_slots(state, &intel_dp-
> > > mst_mgr,
> > -                                                     connector->port,
> > -                                                     crtc_state->pbn,
> > -
> > drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
> > -
> > crtc_state->port_clock,
> > -
> > crtc_state->lane_count));
> > +                                                     connector->port,
> > crtc_state->pbn);
> >                 if (slots == -EDEADLK)
> >                         return slots;
> >                 if (slots >= 0)
> > @@ -360,21 +367,17 @@ static void intel_mst_disable_dp(struct
> > intel_atomic_state *state,
> >         struct intel_dp *intel_dp = &dig_port->dp;
> >         struct intel_connector *connector =
> >                 to_intel_connector(old_conn_state->connector);
> > +       struct drm_dp_mst_topology_state *mst_state =
> > +               drm_atomic_get_mst_topology_state(&state->base,
> > &intel_dp->mst_mgr);
> >         struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > -       int start_slot = intel_dp_is_uhbr(old_crtc_state) ? 0 : 1;
> > -       int ret;
> > 
> >         drm_dbg_kms(&i915->drm, "active links %d\n",
> >                     intel_dp->active_mst_links);
> > 
> >         intel_hdcp_disable(intel_mst->connector);
> > 
> > -       drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, connector-
> > > port);
> > -
> > -       ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr,
> > start_slot);
> > -       if (ret) {
> > -               drm_dbg_kms(&i915->drm, "failed to update payload %d\n",
> > ret);
> > -       }
> > +       drm_dp_remove_payload(&intel_dp->mst_mgr, mst_state,
> > +                             drm_atomic_get_mst_payload_state(mst_state,
> > connector->port));
> > 
> >         intel_audio_codec_disable(encoder, old_crtc_state,
> > old_conn_state);
> >  }
> > @@ -402,8 +405,6 @@ static void intel_mst_post_disable_dp(struct
> > intel_atomic_state *state,
> > 
> >         intel_disable_transcoder(old_crtc_state);
> > 
> > -       drm_dp_update_payload_part2(&intel_dp->mst_mgr);
> > -
> >         clear_act_sent(encoder, old_crtc_state);
> > 
> >         intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(old_crtc_state-
> > > cpu_transcoder),
> > @@ -411,8 +412,6 @@ static void intel_mst_post_disable_dp(struct
> > intel_atomic_state *state,
> > 
> >         wait_for_act_sent(encoder, old_crtc_state);
> > 
> > -       drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, connector-
> > > port);
> > -
> >         intel_ddi_disable_transcoder_func(old_crtc_state);
> > 
> >         if (DISPLAY_VER(dev_priv) >= 9)
> > @@ -479,7 +478,8 @@ static void intel_mst_pre_enable_dp(struct
> > intel_atomic_state *state,
> >         struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >         struct intel_connector *connector =
> >                 to_intel_connector(conn_state->connector);
> > -       int start_slot = intel_dp_is_uhbr(pipe_config) ? 0 : 1;
> > +       struct drm_dp_mst_topology_state *mst_state =
> > +               drm_atomic_get_new_mst_topology_state(&state->base,
> > &intel_dp->mst_mgr);
> >         int ret;
> >         bool first_mst_stream;
> > 
> > @@ -505,16 +505,13 @@ static void intel_mst_pre_enable_dp(struct
> > intel_atomic_state *state,
> >                 dig_port->base.pre_enable(state, &dig_port->base,
> >                                                 pipe_config, NULL);
> > 
> > -       ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
> > -                                      connector->port,
> > -                                      pipe_config->pbn,
> > -                                      pipe_config->dp_m_n.tu);
> > -       if (!ret)
> > -               drm_err(&dev_priv->drm, "failed to allocate vcpi\n");
> > -
> >         intel_dp->active_mst_links++;
> > 
> > -       ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr,
> > start_slot);
> > +       ret = drm_dp_add_payload_part1(&intel_dp->mst_mgr, mst_state,
> > +
> > drm_atomic_get_mst_payload_state(mst_state, connector->port));
> > +       if (ret < 0)
> > +               drm_err(&dev_priv->drm, "Failed to create MST payload for
> > %s: %d\n",
> > +                       connector->base.name, ret);
> > 
> >         /*
> >          * Before Gen 12 this is not done as part of
> > @@ -537,7 +534,10 @@ static void intel_mst_enable_dp(struct
> > intel_atomic_state *state,
> >         struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> >         struct intel_digital_port *dig_port = intel_mst->primary;
> >         struct intel_dp *intel_dp = &dig_port->dp;
> > +       struct intel_connector *connector = to_intel_connector(conn_state-
> > > connector);
> >         struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > +       struct drm_dp_mst_topology_state *mst_state =
> > +               drm_atomic_get_new_mst_topology_state(&state->base,
> > &intel_dp->mst_mgr);
> >         enum transcoder trans = pipe_config->cpu_transcoder;
> > 
> >         drm_WARN_ON(&dev_priv->drm, pipe_config->has_pch_encoder);
> > @@ -565,7 +565,8 @@ static void intel_mst_enable_dp(struct
> > intel_atomic_state *state,
> > 
> >         wait_for_act_sent(encoder, pipe_config);
> > 
> > -       drm_dp_update_payload_part2(&intel_dp->mst_mgr);
> > +       drm_dp_add_payload_part2(&intel_dp->mst_mgr, &state->base,
> > +
> > drm_atomic_get_mst_payload_state(mst_state, connector->port));
> > 
> >         if (DISPLAY_VER(dev_priv) >= 12 && pipe_config->fec_enable)
> >                 intel_de_rmw(dev_priv, CHICKEN_TRANS(trans), 0,
> > @@ -948,8 +949,6 @@ intel_dp_mst_encoder_init(struct intel_digital_port
> > *dig_port, int conn_base_id)
> >         struct intel_dp *intel_dp = &dig_port->dp;
> >         enum port port = dig_port->base.port;
> >         int ret;
> > -       int max_source_rate =
> > -               intel_dp->source_rates[intel_dp->num_source_rates - 1];
> > 
> >         if (!HAS_DP_MST(i915) || intel_dp_is_edp(intel_dp))
> >                 return 0;
> > @@ -965,10 +964,7 @@ intel_dp_mst_encoder_init(struct intel_digital_port
> > *dig_port, int conn_base_id)
> >         /* create encoders */
> >         intel_dp_create_fake_mst_encoders(dig_port);
> >         ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, &i915-
> > > drm,
> > -                                          &intel_dp->aux, 16, 3,
> > -                                          dig_port->max_lanes,
> > -                                          max_source_rate,
> > -                                          conn_base_id);
> > +                                          &intel_dp->aux, 16, 3,
> > conn_base_id);
> >         if (ret) {
> >                 intel_dp->mst_mgr.cbs = NULL;
> >                 return ret;
> > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c
> > b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > index 8ea66a2e1b09..7dbc9f0bb24f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > @@ -30,8 +30,30 @@
> > 
> >  static int intel_conn_to_vcpi(struct intel_connector *connector)
> >  {
> > +       struct drm_dp_mst_topology_mgr *mgr;
> > +       struct drm_dp_mst_atomic_payload *payload;
> > +       struct drm_dp_mst_topology_state *mst_state;
> > +       int vcpi = 0;
> > +
> >         /* For HDMI this is forced to be 0x0. For DP SST also this is 0x0.
> > */
> > -       return connector->port  ? connector->port->vcpi.vcpi : 0;
> > +       if (!connector->port)
> > +               return 0;
> > +       mgr = connector->port->mgr;
> > +
> > +       drm_modeset_lock(&mgr->base.lock, NULL);
> > +       mst_state = to_drm_dp_mst_topology_state(mgr->base.state);
> > +       payload = drm_atomic_get_mst_payload_state(mst_state,
> > connector->port);
> > +       if (drm_WARN_ON(mgr->dev, !payload))
> > +               goto out;
> > +
> > +       vcpi = payload->vcpi;
> > +       if (drm_WARN_ON(mgr->dev, vcpi < 0)) {
> > +               vcpi = 0;
> > +               goto out;
> > +       }
> > +out:
> > +       drm_modeset_unlock(&mgr->base.lock);
> > +       return vcpi;
> >  }
> > 
> >  /*
> > diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > index 57f74cfcdebf..e8f4c806fa39 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > @@ -937,6 +937,7 @@ struct nv50_msto {
> >         struct nv50_head *head;
> >         struct nv50_mstc *mstc;
> >         bool disabled;
> > +       bool enabled;
> >  };
> > 
> >  struct nouveau_encoder *nv50_real_outp(struct drm_encoder *encoder)
> > @@ -952,57 +953,37 @@ struct nouveau_encoder *nv50_real_outp(struct
> > drm_encoder *encoder)
> >         return msto->mstc->mstm->outp;
> >  }
> > 
> > -static struct drm_dp_payload *
> > -nv50_msto_payload(struct nv50_msto *msto)
> > -{
> > -       struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
> > -       struct nv50_mstc *mstc = msto->mstc;
> > -       struct nv50_mstm *mstm = mstc->mstm;
> > -       int vcpi = mstc->port->vcpi.vcpi, i;
> > -
> > -       WARN_ON(!mutex_is_locked(&mstm->mgr.payload_lock));
> > -
> > -       NV_ATOMIC(drm, "%s: vcpi %d\n", msto->encoder.name, vcpi);
> > -       for (i = 0; i < mstm->mgr.max_payloads; i++) {
> > -               struct drm_dp_payload *payload = &mstm->mgr.payloads[i];
> > -               NV_ATOMIC(drm, "%s: %d: vcpi %d start 0x%02x slots
> > 0x%02x\n",
> > -                         mstm->outp->base.base.name, i, payload->vcpi,
> > -                         payload->start_slot, payload->num_slots);
> > -       }
> > -
> > -       for (i = 0; i < mstm->mgr.max_payloads; i++) {
> > -               struct drm_dp_payload *payload = &mstm->mgr.payloads[i];
> > -               if (payload->vcpi == vcpi)
> > -                       return payload;
> > -       }
> > -
> > -       return NULL;
> > -}
> > -
> >  static void
> > -nv50_msto_cleanup(struct nv50_msto *msto)
> > +nv50_msto_cleanup(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct drm_dp_mst_topology_mgr *mgr,
> > +                 struct nv50_msto *msto)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
> > -       struct nv50_mstc *mstc = msto->mstc;
> > -       struct nv50_mstm *mstm = mstc->mstm;
> > -
> > -       if (!msto->disabled)
> > -               return;
> > +       struct drm_dp_mst_atomic_payload *payload =
> > +               drm_atomic_get_mst_payload_state(mst_state, msto-
> > > mstc->port);
> > 
> >         NV_ATOMIC(drm, "%s: msto cleanup\n", msto->encoder.name);
> > 
> > -       drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port);
> > -
> > -       msto->mstc = NULL;
> > -       msto->disabled = false;
> > +       if (msto->disabled) {
> > +               msto->mstc = NULL;
> > +               msto->disabled = false;
> > +       } else if (msto->enabled) {
> > +               drm_dp_add_payload_part2(mgr, state, payload);
> > +               msto->enabled = false;
> > +       }
> >  }
> > 
> >  static void
> > -nv50_msto_prepare(struct nv50_msto *msto)
> > +nv50_msto_prepare(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct drm_dp_mst_topology_mgr *mgr,
> > +                 struct nv50_msto *msto)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
> >         struct nv50_mstc *mstc = msto->mstc;
> >         struct nv50_mstm *mstm = mstc->mstm;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         struct {
> >                 struct nv50_disp_mthd_v1 base;
> >                 struct nv50_disp_sor_dp_mst_vcpi_v0 vcpi;
> > @@ -1014,17 +995,21 @@ nv50_msto_prepare(struct nv50_msto *msto)
> >                                (0x0100 << msto->head->base.index),
> >         };
> > 
> > -       mutex_lock(&mstm->mgr.payload_lock);
> > -
> >         NV_ATOMIC(drm, "%s: msto prepare\n", msto->encoder.name);
> > -       if (mstc->port->vcpi.vcpi > 0) {
> > -               struct drm_dp_payload *payload =
> > nv50_msto_payload(msto);
> > -               if (payload) {
> > -                       args.vcpi.start_slot = payload->start_slot;
> > -                       args.vcpi.num_slots = payload->num_slots;
> > -                       args.vcpi.pbn = mstc->port->vcpi.pbn;
> > -                       args.vcpi.aligned_pbn = mstc->port-
> > > vcpi.aligned_pbn;
> > -               }
> > +
> > +       payload = drm_atomic_get_mst_payload_state(mst_state, mstc-
> > > port);
> > +
> > +       // TODO: Figure out if we want to do a better job of handling VCPI
> > allocation failures here?
> > +       if (msto->disabled) {
> > +               drm_dp_remove_payload(mgr, mst_state, payload);
> > +       } else {
> > +               if (msto->enabled)
> > +                       drm_dp_add_payload_part1(mgr, mst_state,
> > payload);
> > +
> > +               args.vcpi.start_slot = payload->vc_start_slot;
> > +               args.vcpi.num_slots = payload->time_slots;
> > +               args.vcpi.pbn = payload->pbn;
> > +               args.vcpi.aligned_pbn = payload->time_slots * mst_state-
> > > pbn_div;
> >         }
> > 
> >         NV_ATOMIC(drm, "%s: %s: %02x %02x %04x %04x\n",
> > @@ -1033,7 +1018,6 @@ nv50_msto_prepare(struct nv50_msto *msto)
> >                   args.vcpi.pbn, args.vcpi.aligned_pbn);
> > 
> >         nvif_mthd(&drm->display->disp.object, 0, &args, sizeof(args));
> > -       mutex_unlock(&mstm->mgr.payload_lock);
> >  }
> > 
> >  static int
> > @@ -1043,6 +1027,7 @@ nv50_msto_atomic_check(struct drm_encoder
> > *encoder,
> >  {
> >         struct drm_atomic_state *state = crtc_state->state;
> >         struct drm_connector *connector = conn_state->connector;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct nv50_mstc *mstc = nv50_mstc(connector);
> >         struct nv50_mstm *mstm = mstc->mstm;
> >         struct nv50_head_atom *asyh = nv50_head_atom(crtc_state);
> > @@ -1070,8 +1055,18 @@ nv50_msto_atomic_check(struct drm_encoder
> > *encoder,
> >                                                     false);
> >         }
> > 
> > -       slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc-
> > > port,
> > -                                             asyh->dp.pbn, 0);
> > +       mst_state = drm_atomic_get_mst_topology_state(state, &mstm-
> > > mgr);
> > +       if (IS_ERR(mst_state))
> > +               return PTR_ERR(mst_state);
> > +
> > +       if (!mst_state->pbn_div) {
> > +               struct nouveau_encoder *outp = mstc->mstm->outp;
> > +
> > +               mst_state->pbn_div =
> > drm_dp_get_vc_payload_bw(&mstm->mgr,
> > +                                                             outp-
> > >dp.link_bw,
> > outp->dp.link_nr);
> > +       }
> > +
> > +       slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc-
> > > port, asyh->dp.pbn);
> >         if (slots < 0)
> >                 return slots;
> > 
> > @@ -1103,7 +1098,6 @@ nv50_msto_atomic_enable(struct drm_encoder
> > *encoder, struct drm_atomic_state *st
> >         struct drm_connector *connector;
> >         struct drm_connector_list_iter conn_iter;
> >         u8 proto;
> > -       bool r;
> > 
> >         drm_connector_list_iter_begin(encoder->dev, &conn_iter);
> >         drm_for_each_connector_iter(connector, &conn_iter) {
> > @@ -1118,10 +1112,6 @@ nv50_msto_atomic_enable(struct drm_encoder
> > *encoder, struct drm_atomic_state *st
> >         if (WARN_ON(!mstc))
> >                 return;
> > 
> > -       r = drm_dp_mst_allocate_vcpi(&mstm->mgr, mstc->port, asyh-
> > > dp.pbn, asyh->dp.tu);
> > -       if (!r)
> > -               DRM_DEBUG_KMS("Failed to allocate VCPI\n");
> > -
> >         if (!mstm->links++)
> >                 nv50_outp_acquire(mstm->outp, false /*XXX: MST audio.*/);
> > 
> > @@ -1134,6 +1124,7 @@ nv50_msto_atomic_enable(struct drm_encoder
> > *encoder, struct drm_atomic_state *st
> >                            nv50_dp_bpc_to_depth(asyh->or.bpc));
> > 
> >         msto->mstc = mstc;
> > +       msto->enabled = true;
> >         mstm->modified = true;
> >  }
> > 
> > @@ -1144,8 +1135,6 @@ nv50_msto_atomic_disable(struct drm_encoder
> > *encoder, struct drm_atomic_state *s
> >         struct nv50_mstc *mstc = msto->mstc;
> >         struct nv50_mstm *mstm = mstc->mstm;
> > 
> > -       drm_dp_mst_reset_vcpi_slots(&mstm->mgr, mstc->port);
> > -
> >         mstm->outp->update(mstm->outp, msto->head->base.index, NULL,
> > 0, 0);
> >         mstm->modified = true;
> >         if (!--mstm->links)
> > @@ -1365,7 +1354,9 @@ nv50_mstc_new(struct nv50_mstm *mstm, struct
> > drm_dp_mst_port *port,
> >  }
> > 
> >  static void
> > -nv50_mstm_cleanup(struct nv50_mstm *mstm)
> > +nv50_mstm_cleanup(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct nv50_mstm *mstm)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(mstm->outp-
> > > base.base.dev);
> >         struct drm_encoder *encoder;
> > @@ -1373,14 +1364,12 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
> >         NV_ATOMIC(drm, "%s: mstm cleanup\n", mstm->outp-
> > > base.base.name);
> >         drm_dp_check_act_status(&mstm->mgr);
> > 
> > -       drm_dp_update_payload_part2(&mstm->mgr);
> > -
> >         drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> >                 if (encoder->encoder_type ==
> > DRM_MODE_ENCODER_DPMST) {
> >                         struct nv50_msto *msto = nv50_msto(encoder);
> >                         struct nv50_mstc *mstc = msto->mstc;
> >                         if (mstc && mstc->mstm == mstm)
> > -                               nv50_msto_cleanup(msto);
> > +                               nv50_msto_cleanup(state, mst_state,
> > &mstm->mgr, msto);
> >                 }
> >         }
> > 
> > @@ -1388,20 +1377,34 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
> >  }
> > 
> >  static void
> > -nv50_mstm_prepare(struct nv50_mstm *mstm)
> > +nv50_mstm_prepare(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct nv50_mstm *mstm)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(mstm->outp-
> > > base.base.dev);
> >         struct drm_encoder *encoder;
> > 
> >         NV_ATOMIC(drm, "%s: mstm prepare\n", mstm->outp-
> > > base.base.name);
> > -       drm_dp_update_payload_part1(&mstm->mgr, 1);
> > 
> > +       /* Disable payloads first */
> >         drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> >                 if (encoder->encoder_type ==
> > DRM_MODE_ENCODER_DPMST) {
> >                         struct nv50_msto *msto = nv50_msto(encoder);
> >                         struct nv50_mstc *mstc = msto->mstc;
> > -                       if (mstc && mstc->mstm == mstm)
> > -                               nv50_msto_prepare(msto);
> > +                       if (mstc && mstc->mstm == mstm && msto->disabled)
> > +                               nv50_msto_prepare(state, mst_state,
> > &mstm->mgr, msto);
> > +               }
> > +       }
> > +
> > +       /* Add payloads for new heads, while also updating the start slots
> > of
> > any unmodified (but
> > +        * active) heads that may have had their VC slots shifted left
> > after the
> > previous step
> > +        */
> > +       drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> > +               if (encoder->encoder_type ==
> > DRM_MODE_ENCODER_DPMST) {
> > +                       struct nv50_msto *msto = nv50_msto(encoder);
> > +                       struct nv50_mstc *mstc = msto->mstc;
> > +                       if (mstc && mstc->mstm == mstm && !msto-
> > > disabled)
> > +                               nv50_msto_prepare(state, mst_state,
> > &mstm->mgr, msto);
> >                 }
> >         }
> > 
> > @@ -1598,9 +1601,7 @@ nv50_mstm_new(struct nouveau_encoder *outp,
> > struct drm_dp_aux *aux, int aux_max,
> >         mstm->mgr.cbs = &nv50_mstm;
> > 
> >         ret = drm_dp_mst_topology_mgr_init(&mstm->mgr, dev, aux,
> > aux_max,
> > -                                          max_payloads, outp->dcb-
> > > dpconf.link_nr,
> > -
> > drm_dp_bw_code_to_link_rate(outp->dcb->dpconf.link_bw),
> > -                                          conn_base_id);
> > +                                          max_payloads, conn_base_id);
> >         if (ret)
> >                 return ret;
> > 
> > @@ -2045,20 +2046,20 @@ nv50_pior_create(struct drm_connector
> > *connector, struct dcb_output *dcbe)
> >  static void
> >  nv50_disp_atomic_commit_core(struct drm_atomic_state *state, u32
> > *interlock)
> >  {
> > +       struct drm_dp_mst_topology_mgr *mgr;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct nouveau_drm *drm = nouveau_drm(state->dev);
> >         struct nv50_disp *disp = nv50_disp(drm->dev);
> >         struct nv50_core *core = disp->core;
> >         struct nv50_mstm *mstm;
> > -       struct drm_encoder *encoder;
> > +       int i;
> > 
> >         NV_ATOMIC(drm, "commit core %08x\n",
> > interlock[NV50_DISP_INTERLOCK_BASE]);
> > 
> > -       drm_for_each_encoder(encoder, drm->dev) {
> > -               if (encoder->encoder_type !=
> > DRM_MODE_ENCODER_DPMST) {
> > -                       mstm = nouveau_encoder(encoder)->dp.mstm;
> > -                       if (mstm && mstm->modified)
> > -                               nv50_mstm_prepare(mstm);
> > -               }
> > +       for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> > +               mstm = nv50_mstm(mgr);
> > +               if (mstm->modified)
> > +                       nv50_mstm_prepare(state, mst_state, mstm);
> >         }
> > 
> >         core->func->ntfy_init(disp->sync, NV50_DISP_CORE_NTFY);
> > @@ -2067,12 +2068,10 @@ nv50_disp_atomic_commit_core(struct
> > drm_atomic_state *state, u32 *interlock)
> >                                        disp->core->chan.base.device))
> >                 NV_ERROR(drm, "core notifier timeout\n");
> > 
> > -       drm_for_each_encoder(encoder, drm->dev) {
> > -               if (encoder->encoder_type !=
> > DRM_MODE_ENCODER_DPMST) {
> > -                       mstm = nouveau_encoder(encoder)->dp.mstm;
> > -                       if (mstm && mstm->modified)
> > -                               nv50_mstm_cleanup(mstm);
> > -               }
> > +       for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> > +               mstm = nv50_mstm(mgr);
> > +               if (mstm->modified)
> > +                       nv50_mstm_cleanup(state, mst_state, mstm);
> >         }
> >  }
> > 
> > diff --git a/include/drm/display/drm_dp_mst_helper.h
> > b/include/drm/display/drm_dp_mst_helper.h
> > index ecd130028337..6317831705ab 100644
> > --- a/include/drm/display/drm_dp_mst_helper.h
> > +++ b/include/drm/display/drm_dp_mst_helper.h
> > @@ -48,20 +48,6 @@ struct drm_dp_mst_topology_ref_history {
> > 
> >  struct drm_dp_mst_branch;
> > 
> > -/**
> > - * struct drm_dp_vcpi - Virtual Channel Payload Identifier
> > - * @vcpi: Virtual channel ID.
> > - * @pbn: Payload Bandwidth Number for this channel
> > - * @aligned_pbn: PBN aligned with slot size
> > - * @num_slots: number of slots for this PBN
> > - */
> > -struct drm_dp_vcpi {
> > -       int vcpi;
> > -       int pbn;
> > -       int aligned_pbn;
> > -       int num_slots;
> > -};
> > -
> >  /**
> >   * struct drm_dp_mst_port - MST port
> >   * @port_num: port number
> > @@ -142,7 +128,6 @@ struct drm_dp_mst_port {
> >         struct drm_dp_aux aux; /* i2c bus for this port? */
> >         struct drm_dp_mst_branch *parent;
> > 
> > -       struct drm_dp_vcpi vcpi;
> >         struct drm_connector *connector;
> >         struct drm_dp_mst_topology_mgr *mgr;
> > 
> > @@ -527,19 +512,6 @@ struct drm_dp_mst_topology_cbs {
> >         void (*poll_hpd_irq)(struct drm_dp_mst_topology_mgr *mgr);
> >  };
> > 
> > -#define DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
> > -
> > -#define DP_PAYLOAD_LOCAL 1
> > -#define DP_PAYLOAD_REMOTE 2
> > -#define DP_PAYLOAD_DELETE_LOCAL 3
> > -
> > -struct drm_dp_payload {
> > -       int payload_state;
> > -       int start_slot;
> > -       int num_slots;
> > -       int vcpi;
> > -};
> > -
> >  #define to_dp_mst_topology_state(x) container_of(x, struct
> > drm_dp_mst_topology_state, base)
> > 
> >  /**
> > @@ -551,6 +523,35 @@ struct drm_dp_payload {
> >  struct drm_dp_mst_atomic_payload {
> >         /** @port: The MST port assigned to this payload */
> >         struct drm_dp_mst_port *port;
> > +
> > +       /**
> > +        * @vc_start_slot: The time slot that this payload starts on.
> > Because
> > payload start slots
> > +        * can't be determined ahead of time, the contents of this value
> > are
> > UNDEFINED at atomic
> > +        * check time. This shouldn't usually matter, as the start slot
> > should
> > never be relevant for
> > +        * atomic state computations.
> > +        *
> > +        * Since this value is determined at commit time instead of check
> > time, this value is
> > +        * protected by the MST helpers ensuring that async commits
> > operating on the given topology
> > +        * never run in parallel. In the event that a driver does need to
> > read
> > this value (e.g. to
> > +        * inform hardware of the starting timeslot for a payload), the
> > driver
> > may either:
> > +        *
> > +        * * Read this field during the atomic commit after
> > +        *   drm_dp_mst_atomic_wait_for_dependencies() has been called,
> > which will ensure the
> > +        *   previous MST states payload start slots have been copied over
> > to
> > the new state. Note
> > +        *   that a new start slot won't be assigned/removed from this
> > payload until
> > +        *   drm_dp_add_payload_part1()/drm_dp_remove_payload() have
> > been called.
> > +        * * Acquire the MST modesetting lock, and then wait for any
> > pending MST-related commits to
> > +        *   get committed to hardware by calling drm_crtc_commit_wait()
> > on
> > each of the
> > +        *   &drm_crtc_commit structs in
> > &drm_dp_mst_topology_state.commit_deps.
> > +        *
> > +        * If neither of the two above solutions suffice (e.g. the driver
> > needs
> > to read the start
> > +        * slot in the middle of an atomic commit without waiting for some
> > reason), then drivers
> > +        * should cache this value themselves after changing payloads.
> > +        */
> > +       s8 vc_start_slot;
> > +
> > +       /** @vcpi: The Virtual Channel Payload Identifier */
> > +       u8 vcpi;
> >         /** @time_slots: The number of timeslots allocated to this payload
> > */
> >         int time_slots;
> >         /** @pbn: The payload bandwidth for this payload */
> > @@ -574,8 +575,6 @@ struct drm_dp_mst_topology_state {
> >         /** @base: Base private state for atomic */
> >         struct drm_private_state base;
> > 
> > -       /** @payloads: The list of payloads being created/destroyed in
> > this
> > state */
> > -       struct list_head payloads;
> >         /** @mgr: The topology manager */
> >         struct drm_dp_mst_topology_mgr *mgr;
> > 
> > @@ -592,10 +591,21 @@ struct drm_dp_mst_topology_state {
> >         /** @num_commit_deps: The number of CRTC commits in
> > @commit_deps */
> >         size_t num_commit_deps;
> > 
> > +       /** @payload_mask: A bitmask of allocated VCPIs, used for VCPI
> > assignments */
> > +       u32 payload_mask;
> > +       /** @payloads: The list of payloads being created/destroyed in
> > this
> > state */
> > +       struct list_head payloads;
> > +
> >         /** @total_avail_slots: The total number of slots this topology
> > can
> > handle (63 or 64) */
> >         u8 total_avail_slots;
> >         /** @start_slot: The first usable time slot in this topology (1 or
> > 0) */
> >         u8 start_slot;
> > +
> > +       /**
> > +        * @pbn_div: The current PBN divisor for this topology. The driver
> > is
> > expected to fill this
> > +        * out itself.
> > +        */
> > +       int pbn_div;
> >  };
> > 
> >  #define to_dp_mst_topology_mgr(x) container_of(x, struct
> > drm_dp_mst_topology_mgr, base)
> > @@ -635,14 +645,6 @@ struct drm_dp_mst_topology_mgr {
> >          * @max_payloads: maximum number of payloads the GPU can
> > generate.
> >          */
> >         int max_payloads;
> > -       /**
> > -        * @max_lane_count: maximum number of lanes the GPU can drive.
> > -        */
> > -       int max_lane_count;
> > -       /**
> > -        * @max_link_rate: maximum link rate per lane GPU can output, in
> > kHz.
> > -        */
> > -       int max_link_rate;
> >         /**
> >          * @conn_base_id: DRM connector ID this mgr is connected to. Only
> > used
> >          * to build the MST connector path value.
> > @@ -685,6 +687,20 @@ struct drm_dp_mst_topology_mgr {
> >          */
> >         bool payload_id_table_cleared : 1;
> > 
> > +       /**
> > +        * @payload_count: The number of currently active payloads in
> > hardware. This value is only
> > +        * intended to be used internally by MST helpers for payload
> > tracking,
> > and is only safe to
> > +        * read/write from the atomic commit (not check) context.
> > +        */
> > +       u8 payload_count;
> > +
> > +       /**
> > +        * @next_start_slot: The starting timeslot to use for new VC
> > payloads.
> > This value is used
> > +        * internally by MST helpers for payload tracking, and is only
> > safe to
> > read/write from the
> > +        * atomic commit (not check) context.
> > +        */
> > +       u8 next_start_slot;
> > +
> >         /**
> >          * @mst_primary: Pointer to the primary/first branch device.
> >          */
> > @@ -698,10 +714,6 @@ struct drm_dp_mst_topology_mgr {
> >          * @sink_count: Sink count from DEVICE_SERVICE_IRQ_VECTOR_ESI0.
> >          */
> >         u8 sink_count;
> > -       /**
> > -        * @pbn_div: PBN to slots divisor.
> > -        */
> > -       int pbn_div;
> > 
> >         /**
> >          * @funcs: Atomic helper callbacks
> > @@ -718,32 +730,6 @@ struct drm_dp_mst_topology_mgr {
> >          */
> >         struct list_head tx_msg_downq;
> > 
> > -       /**
> > -        * @payload_lock: Protect payload information.
> > -        */
> > -       struct mutex payload_lock;
> > -       /**
> > -        * @proposed_vcpis: Array of pointers for the new VCPI allocation.
> > The
> > -        * VCPI structure itself is &drm_dp_mst_port.vcpi, and the size of
> > -        * this array is determined by @max_payloads.
> > -        */
> > -       struct drm_dp_vcpi **proposed_vcpis;
> > -       /**
> > -        * @payloads: Array of payloads. The size of this array is
> > determined
> > -        * by @max_payloads.
> > -        */
> > -       struct drm_dp_payload *payloads;
> > -       /**
> > -        * @payload_mask: Elements of @payloads actually in use. Since
> > -        * reallocation of active outputs isn't possible gaps can be
> > created by
> > -        * disabling outputs out of order compared to how they've been
> > enabled.
> > -        */
> > -       unsigned long payload_mask;
> > -       /**
> > -        * @vcpi_mask: Similar to @payload_mask, but for @proposed_vcpis.
> > -        */
> > -       unsigned long vcpi_mask;
> > -
> >         /**
> >          * @tx_waitq: Wait to queue stall for the tx worker.
> >          */
> > @@ -815,9 +801,7 @@ struct drm_dp_mst_topology_mgr {
> >  int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr
> > *mgr,
> >                                  struct drm_device *dev, struct drm_dp_aux
> > *aux,
> >                                  int max_dpcd_transaction_bytes,
> > -                                int max_payloads,
> > -                                int max_lane_count, int max_link_rate,
> > -                                int conn_base_id);
> > +                                int max_payloads, int conn_base_id);
> > 
> >  void drm_dp_mst_topology_mgr_destroy(struct
> > drm_dp_mst_topology_mgr *mgr);
> > 
> > @@ -840,28 +824,17 @@ int drm_dp_get_vc_payload_bw(const struct
> > drm_dp_mst_topology_mgr *mgr,
> > 
> >  int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc);
> > 
> > -bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                             struct drm_dp_mst_port *port, int pbn, int
> > slots);
> > -
> > -int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > struct drm_dp_mst_port *port);
> > -
> > -
> > -void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr
> > *mgr, struct drm_dp_mst_port *port);
> > -
> >  void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state
> > *mst_state, uint8_t link_encoding_cap);
> > 
> > -void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                               struct drm_dp_mst_port *port);
> > -
> > -
> > -int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > -                          int pbn);
> > -
> > -
> > -int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr
> > *mgr, int start_slot);
> > -
> > -
> > -int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr
> > *mgr);
> > +int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_dp_mst_topology_state *mst_state,
> > +                            struct drm_dp_mst_atomic_payload *payload);
> > +int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_atomic_state *state,
> > +                            struct drm_dp_mst_atomic_payload *payload);
> > +void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
> > +                          struct drm_dp_mst_topology_state *mst_state,
> > +                          struct drm_dp_mst_atomic_payload *payload);
> > 
> >  int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);
> > 
> > @@ -883,17 +856,22 @@ int drm_dp_mst_connector_late_register(struct
> > drm_connector *connector,
> >  void drm_dp_mst_connector_early_unregister(struct drm_connector
> > *connector,
> >                                            struct drm_dp_mst_port *port);
> > 
> > -struct drm_dp_mst_topology_state
> > *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> > -                                                                   struct
> > drm_dp_mst_topology_mgr *mgr);
> > +struct drm_dp_mst_topology_state *
> > +drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> > +                                 struct drm_dp_mst_topology_mgr *mgr);
> > +struct drm_dp_mst_topology_state *
> > +drm_atomic_get_new_mst_topology_state(struct drm_atomic_state
> > *state,
> > +                                     struct drm_dp_mst_topology_mgr
> > *mgr);
> > +struct drm_dp_mst_atomic_payload *
> > +drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state
> > *state,
> > +                                struct drm_dp_mst_port *port);
> >  int __must_check
> >  drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> >                               struct drm_dp_mst_topology_mgr *mgr,
> > -                             struct drm_dp_mst_port *port, int pbn,
> > -                             int pbn_div);
> > +                             struct drm_dp_mst_port *port, int pbn);
> >  int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
> >                                  struct drm_dp_mst_port *port,
> > -                                int pbn, int pbn_div,
> > -                                bool enable);
> > +                                int pbn, bool enable);
> >  int __must_check
> >  drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
> >                                   struct drm_dp_mst_topology_mgr *mgr);
> > @@ -917,6 +895,12 @@ void drm_dp_mst_put_port_malloc(struct
> > drm_dp_mst_port *port);
> > 
> >  struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct
> > drm_dp_mst_port *port);
> > 
> > +static inline struct drm_dp_mst_topology_state *
> > +to_drm_dp_mst_topology_state(struct drm_private_state *state)
> > +{
> > +       return container_of(state, struct drm_dp_mst_topology_state,
> > base);
> > +}
> > +
> >  extern const struct drm_private_state_funcs
> > drm_dp_mst_topology_state_funcs;
> > 
> >  /**
> > --
> > 2.35.3
> 
> --
> Regards,
> Wayne Lin

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat