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Date:   Thu, 16 May 2019 15:00:01 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Sean Paul <sean@poorly.run>
Cc:     dri-devel <dri-devel@lists.freedesktop.org>,
        Sean Paul <seanpaul@chromium.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Ville =?utf-8?B?U3lyasOkbMOk?= <ville.syrjala@linux.intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        Eric Anholt <eric@anholt.net>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        David Airlie <airlied@linux.ie>,
        LKML <linux-kernel@vger.kernel.org>,
        Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        nouveau <nouveau@lists.freedesktop.org>,
        linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v3 04/10] drm: Convert
 connector_helper_funcs->atomic_check to accept drm_atomic_state
Message-ID: <20190516120001.GH14820@pendragon.ideasonboard.com>
References: <20190502194956.218441-1-sean@poorly.run>
 <20190502194956.218441-5-sean@poorly.run>
 <20190511191202.GL13043@pendragon.ideasonboard.com>
 <CAMavQKKS5ek1cAZRZfx91TA_-gXBvuNfbvHDo_jetnSL9jmibw@mail.gmail.com>
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In-Reply-To: <CAMavQKKS5ek1cAZRZfx91TA_-gXBvuNfbvHDo_jetnSL9jmibw@mail.gmail.com>
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Hi Sean,

On Mon, May 13, 2019 at 10:38:58AM -0400, Sean Paul wrote:
> On Sat, May 11, 2019 at 3:12 PM Laurent Pinchart wrote:
> > On Thu, May 02, 2019 at 03:49:46PM -0400, Sean Paul wrote:
> >> From: Sean Paul <seanpaul@chromium.org>
> >>
> >> Everyone who implements connector_helper_funcs->atomic_check reaches
> >> into the connector state to get the atomic state. Instead of continuing
> >> this pattern, change the callback signature to just give atomic state
> >> and let the driver determine what it does and does not need from it.
> >>
> >> Eventually all atomic functions should do this, but that's just too much
> >> busy work for me.
> >
> > Given that drivers also access the connector state, isn't this slightly
> > more inefficient ?
> 
> Inefficient in terms of what?

In terms of the operation having to lookup the connector state, when the
caller has it and can easily pass it. As Daniel commented, this may be
the price to pay for a cleaner API, but I wonder how much overhead all
the state tracking is costing.

> Agree that in isolation this patch might seem unnecessary, but it ties
> in with the encoder and bridge CLs which accept drm_atomic_state in

CLs ?

> their hooks. In general the idea is to convert all atomic functions to
> take overall atomic state instead of just their object state. Reality
> has proven to be more complicated and we need more access than what
> the current implementation provides.
> 
> Sean
> 
> >> Changes in v3:
> >> - Added to the set
> >>
> >> Cc: Daniel Vetter <daniel@ffwll.ch>
> >> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> >> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> >> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> >> Cc: Ben Skeggs <bskeggs@redhat.com>
> >> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> >> Cc: Eric Anholt <eric@anholt.net>
> >> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> >> ---
> >>  drivers/gpu/drm/drm_atomic_helper.c      |  4 ++--
> >>  drivers/gpu/drm/i915/intel_atomic.c      |  8 +++++---
> >>  drivers/gpu/drm/i915/intel_dp_mst.c      |  7 ++++---
> >>  drivers/gpu/drm/i915/intel_drv.h         |  2 +-
> >>  drivers/gpu/drm/i915/intel_sdvo.c        |  9 +++++----
> >>  drivers/gpu/drm/i915/intel_tv.c          |  8 +++++---
> >>  drivers/gpu/drm/nouveau/dispnv50/disp.c  |  5 +++--
> >>  drivers/gpu/drm/rcar-du/rcar_lvds.c      | 12 +++++++-----
> >>  drivers/gpu/drm/vc4/vc4_txp.c            |  7 ++++---
> >>  include/drm/drm_modeset_helper_vtables.h |  2 +-
> >>  10 files changed, 37 insertions(+), 27 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> >> index 9d9e47276839..fa5a367507c1 100644
> >> --- a/drivers/gpu/drm/drm_atomic_helper.c
> >> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> >> @@ -683,7 +683,7 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
> >>               }
> >>
> >>               if (funcs->atomic_check)
> >> -                     ret = funcs->atomic_check(connector, new_connector_state);
> >> +                     ret = funcs->atomic_check(connector, state);
> >>               if (ret)
> >>                       return ret;
> >>
> >> @@ -725,7 +725,7 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
> >>                       continue;
> >>
> >>               if (funcs->atomic_check)
> >> -                     ret = funcs->atomic_check(connector, new_connector_state);
> >> +                     ret = funcs->atomic_check(connector, state);
> >>               if (ret)
> >>                       return ret;
> >>       }
> >> diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
> >> index b844e8840c6f..e8a5b82e9242 100644
> >> --- a/drivers/gpu/drm/i915/intel_atomic.c
> >> +++ b/drivers/gpu/drm/i915/intel_atomic.c
> >> @@ -103,12 +103,14 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
> >>  }
> >>
> >>  int intel_digital_connector_atomic_check(struct drm_connector *conn,
> >> -                                      struct drm_connector_state *new_state)
> >> +                                      struct drm_atomic_state *state)
> >>  {
> >> +     struct drm_connector_state *new_state =
> >> +             drm_atomic_get_new_connector_state(state, conn);
> >>       struct intel_digital_connector_state *new_conn_state =
> >>               to_intel_digital_connector_state(new_state);
> >>       struct drm_connector_state *old_state =
> >> -             drm_atomic_get_old_connector_state(new_state->state, conn);
> >> +             drm_atomic_get_old_connector_state(state, conn);
> >>       struct intel_digital_connector_state *old_conn_state =
> >>               to_intel_digital_connector_state(old_state);
> >>       struct drm_crtc_state *crtc_state;
> >> @@ -118,7 +120,7 @@ int intel_digital_connector_atomic_check(struct drm_connector *conn,
> >>       if (!new_state->crtc)
> >>               return 0;
> >>
> >> -     crtc_state = drm_atomic_get_new_crtc_state(new_state->state, new_state->crtc);
> >> +     crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
> >>
> >>       /*
> >>        * These properties are handled by fastset, and might not end
> >> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> >> index 19d81cef2ab6..89cfec128ba0 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> >> @@ -143,9 +143,10 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >>
> >>  static int
> >>  intel_dp_mst_atomic_check(struct drm_connector *connector,
> >> -                       struct drm_connector_state *new_conn_state)
> >> +                       struct drm_atomic_state *state)
> >>  {
> >> -     struct drm_atomic_state *state = new_conn_state->state;
> >> +     struct drm_connector_state *new_conn_state =
> >> +             drm_atomic_get_new_connector_state(state, connector);
> >>       struct drm_connector_state *old_conn_state =
> >>               drm_atomic_get_old_connector_state(state, connector);
> >>       struct intel_connector *intel_connector =
> >> @@ -155,7 +156,7 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
> >>       struct drm_dp_mst_topology_mgr *mgr;
> >>       int ret;
> >>
> >> -     ret = intel_digital_connector_atomic_check(connector, new_conn_state);
> >> +     ret = intel_digital_connector_atomic_check(connector, state);
> >>       if (ret)
> >>               return ret;
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >> index f8c7b291fdc3..88571b8e8d62 100644
> >> --- a/drivers/gpu/drm/i915/intel_drv.h
> >> +++ b/drivers/gpu/drm/i915/intel_drv.h
> >> @@ -2481,7 +2481,7 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
> >>                                               struct drm_property *property,
> >>                                               u64 val);
> >>  int intel_digital_connector_atomic_check(struct drm_connector *conn,
> >> -                                      struct drm_connector_state *new_state);
> >> +                                      struct drm_atomic_state *state);
> >>  struct drm_connector_state *
> >>  intel_digital_connector_duplicate_state(struct drm_connector *connector);
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> >> index 68f497493d43..72ea164b971c 100644
> >> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> >> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> >> @@ -2342,9 +2342,10 @@ static const struct drm_connector_funcs intel_sdvo_connector_funcs = {
> >>  };
> >>
> >>  static int intel_sdvo_atomic_check(struct drm_connector *conn,
> >> -                                struct drm_connector_state *new_conn_state)
> >> +                                struct drm_atomic_state *state)
> >>  {
> >> -     struct drm_atomic_state *state = new_conn_state->state;
> >> +     struct drm_connector_state *new_conn_state =
> >> +             drm_atomic_get_new_connector_state(state, conn);
> >>       struct drm_connector_state *old_conn_state =
> >>               drm_atomic_get_old_connector_state(state, conn);
> >>       struct intel_sdvo_connector_state *old_state =
> >> @@ -2356,13 +2357,13 @@ static int intel_sdvo_atomic_check(struct drm_connector *conn,
> >>           (memcmp(&old_state->tv, &new_state->tv, sizeof(old_state->tv)) ||
> >>            memcmp(&old_conn_state->tv, &new_conn_state->tv, sizeof(old_conn_state->tv)))) {
> >>               struct drm_crtc_state *crtc_state =
> >> -                     drm_atomic_get_new_crtc_state(new_conn_state->state,
> >> +                     drm_atomic_get_new_crtc_state(state,
> >>                                                     new_conn_state->crtc);
> >>
> >>               crtc_state->connectors_changed = true;
> >>       }
> >>
> >> -     return intel_digital_connector_atomic_check(conn, new_conn_state);
> >> +     return intel_digital_connector_atomic_check(conn, state);
> >>  }
> >>
> >>  static const struct drm_connector_helper_funcs intel_sdvo_connector_helper_funcs = {
> >> diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
> >> index 3924c4944e1f..a41c5b467c14 100644
> >> --- a/drivers/gpu/drm/i915/intel_tv.c
> >> +++ b/drivers/gpu/drm/i915/intel_tv.c
> >> @@ -1817,16 +1817,18 @@ static const struct drm_connector_funcs intel_tv_connector_funcs = {
> >>  };
> >>
> >>  static int intel_tv_atomic_check(struct drm_connector *connector,
> >> -                              struct drm_connector_state *new_state)
> >> +                              struct drm_atomic_state *state)
> >>  {
> >> +     struct drm_connector_state *new_state;
> >>       struct drm_crtc_state *new_crtc_state;
> >>       struct drm_connector_state *old_state;
> >>
> >> +     new_state = drm_atomic_get_new_connector_state(state, connector);
> >>       if (!new_state->crtc)
> >>               return 0;
> >>
> >> -     old_state = drm_atomic_get_old_connector_state(new_state->state, connector);
> >> -     new_crtc_state = drm_atomic_get_new_crtc_state(new_state->state, new_state->crtc);
> >> +     old_state = drm_atomic_get_old_connector_state(state, connector);
> >> +     new_crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
> >>
> >>       if (old_state->tv.mode != new_state->tv.mode ||
> >>           old_state->tv.margins.left != new_state->tv.margins.left ||
> >> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> >> index 4b1650f51955..7ba373f493b2 100644
> >> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> >> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> >> @@ -948,11 +948,12 @@ nv50_mstc_get_modes(struct drm_connector *connector)
> >>
> >>  static int
> >>  nv50_mstc_atomic_check(struct drm_connector *connector,
> >> -                    struct drm_connector_state *new_conn_state)
> >> +                    struct drm_atomic_state *state)
> >>  {
> >> -     struct drm_atomic_state *state = new_conn_state->state;
> >>       struct nv50_mstc *mstc = nv50_mstc(connector);
> >>       struct drm_dp_mst_topology_mgr *mgr = &mstc->mstm->mgr;
> >> +     struct drm_connector_state *new_conn_state =
> >> +             drm_atomic_get_new_connector_state(state, connector);
> >>       struct drm_connector_state *old_conn_state =
> >>               drm_atomic_get_old_connector_state(state, connector);
> >>       struct drm_crtc_state *crtc_state;
> >> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> >> index 620b51aab291..5b81ba2a7f27 100644
> >> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> >> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> >> @@ -92,13 +92,15 @@ static int rcar_lvds_connector_get_modes(struct drm_connector *connector)
> >>  }
> >>
> >>  static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
> >> -                                         struct drm_connector_state *state)
> >> +                                         struct drm_atomic_state *state)
> >>  {
> >>       struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
> >>       const struct drm_display_mode *panel_mode;
> >> +     struct drm_connector_state *conn_state;
> >>       struct drm_crtc_state *crtc_state;
> >>
> >> -     if (!state->crtc)
> >> +     conn_state = drm_atomic_get_new_connector_state(state, connector);
> >> +     if (!conn_state->crtc)
> >>               return 0;
> >>
> >>       if (list_empty(&connector->modes)) {
> >> @@ -110,9 +112,9 @@ static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
> >>                                     struct drm_display_mode, head);
> >>
> >>       /* We're not allowed to modify the resolution. */
> >> -     crtc_state = drm_atomic_get_crtc_state(state->state, state->crtc);
> >> -     if (IS_ERR(crtc_state))
> >> -             return PTR_ERR(crtc_state);
> >> +     crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
> >> +     if (!crtc_state)
> >> +             return -EINVAL;
> >>
> >>       if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
> >>           crtc_state->mode.vdisplay != panel_mode->vdisplay)
> >> diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
> >> index c8b89a78f9f4..96f91c1b4b6e 100644
> >> --- a/drivers/gpu/drm/vc4/vc4_txp.c
> >> +++ b/drivers/gpu/drm/vc4/vc4_txp.c
> >> @@ -221,17 +221,18 @@ static const u32 txp_fmts[] = {
> >>  };
> >>
> >>  static int vc4_txp_connector_atomic_check(struct drm_connector *conn,
> >> -                                     struct drm_connector_state *conn_state)
> >> +                                       struct drm_atomic_state *state)
> >>  {
> >> +     struct drm_connector_state *conn_state;
> >>       struct drm_crtc_state *crtc_state;
> >>       struct drm_framebuffer *fb;
> >>       int i;
> >>
> >> +     conn_state = drm_atomic_get_new_connector_state(state, conn);
> >>       if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
> >>               return 0;
> >>
> >> -     crtc_state = drm_atomic_get_new_crtc_state(conn_state->state,
> >> -                                                conn_state->crtc);
> >> +     crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
> >>
> >>       fb = conn_state->writeback_job->fb;
> >>       if (fb->width != crtc_state->mode.hdisplay ||
> >> diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> >> index de57fb40cb6e..adc8b7cf64b5 100644
> >> --- a/include/drm/drm_modeset_helper_vtables.h
> >> +++ b/include/drm/drm_modeset_helper_vtables.h
> >> @@ -1020,7 +1020,7 @@ struct drm_connector_helper_funcs {
> >>        * deadlock.
> >>        */
> >>       int (*atomic_check)(struct drm_connector *connector,
> >> -                         struct drm_connector_state *state);
> >> +                         struct drm_atomic_state *state);
> >>
> >>       /**
> >>        * @atomic_commit:

-- 
Regards,

Laurent Pinchart