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Date:   Wed, 17 Feb 2021 09:52:33 +0200
From:   Imre Deak <imre.deak@intel.com>
To:     Lyude Paul <lyude@redhat.com>
Cc:     intel-gfx@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>
Subject: Re: [Intel-gfx] [PATCH v2] drm/i915/gen9bc: Handle TGP PCH during
 suspend/resume
Message-ID: <20210217075233.GA443835@ideak-desk.fi.intel.com>
Reply-To: imre.deak@intel.com
References: <20210212185053.1689716-1-lyude@redhat.com>
 <20210216180825.GA420119@ideak-desk.fi.intel.com>
 <de45c8434b35ba9c712edf615bea4f86131aaf1a.camel@redhat.com>
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On Tue, Feb 16, 2021 at 09:36:01PM -0500, Lyude Paul wrote:
> On Tue, 2021-02-16 at 20:08 +0200, Imre Deak wrote:
> > Hi,
> > 
> > thanks for respinning this patchset, some comments below.
> > 
> > On Fri, Feb 12, 2021 at 01:50:53PM -0500, Lyude Paul wrote:
> > > From: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com>
> > > 
> > > For Legacy S3 suspend/resume GEN9 BC needs to enable and
> > > setup TGP PCH.
> > > 
> > > v2:
> > > * Move Wa_14010685332 into it's own function - vsyrjala
> > > * Add TODO comment about figuring out if we can move this workaround - imre
> > > 
> > > Cc: Matt Roper <matthew.d.roper@intel.com>
> > > Signed-off-by: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com>
> > > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > > ---
> > > ?drivers/gpu/drm/i915/i915_irq.c | 53 ++++++++++++++++++++++-----------
> > > ?1 file changed, 36 insertions(+), 17 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_irq.c
> > > b/drivers/gpu/drm/i915/i915_irq.c
> > > index 98145a7f28a4..7d912aa950ee 100644
> > > --- a/drivers/gpu/drm/i915/i915_irq.c
> > > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > > @@ -3040,6 +3040,19 @@ static void valleyview_irq_reset(struct
> > > drm_i915_private *dev_priv)
> > > ????????spin_unlock_irq(&dev_priv->irq_lock);
> > > ?}
> > > ?
> > > +static void cnp_irq_post_reset(struct drm_i915_private *dev_priv)
> > 
> > Maybe a better name is cnp_display_clock_wa.
> > 
> > > +{
> > > +???????struct intel_uncore *uncore = &dev_priv->uncore;
> > > +
> > > +???????/*
> > > +??????? * Wa_14010685332:cnp/cmp,tgp,adp
> > 
> > Bspec says this WA applies ICL onwards and it's not PCH specific, for
> > instance I haven't found the GEN9/CNP/CMP WA entries for it. Please also
> > add a 'clarify platforms where this applies' todo item.
> > 
> > > +??????? * TODO: Figure out if this workaround can be applied in the s0ix
> > > suspend/resume handlers as
> > > +??????? * on earlier platforms and whether the workaround is also needed
> > > for runtime suspend/resume
> > > +??????? */
> > > +???????intel_uncore_rmw(uncore, SOUTH_CHICKEN1, SBCLK_RUN_REFCLK_DIS,
> > > SBCLK_RUN_REFCLK_DIS);
> > > +???????intel_uncore_rmw(uncore, SOUTH_CHICKEN1, SBCLK_RUN_REFCLK_DIS, 0);
> > > +}
> > > +
> > > ?static void gen8_irq_reset(struct drm_i915_private *dev_priv)
> > > ?{
> > > ????????struct intel_uncore *uncore = &dev_priv->uncore;
> > > @@ -3061,8 +3074,14 @@ static void gen8_irq_reset(struct drm_i915_private
> > > *dev_priv)
> > > ????????GEN3_IRQ_RESET(uncore, GEN8_DE_MISC_);
> > > ????????GEN3_IRQ_RESET(uncore, GEN8_PCU_);
> > > ?
> > > -???????if (HAS_PCH_SPLIT(dev_priv))
> > > +???????if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
> > 
> > It was mentioned already earlier, why is this check necessary and can't we
> > just call ibx_irq_reset() for all PCHs?
> > 
> > > +???????????????GEN3_IRQ_RESET(uncore, SDE);
> > > +???????else if (HAS_PCH_SPLIT(dev_priv))
> > > ????????????????ibx_irq_reset(dev_priv);
> > > +
> > > +???????if (INTEL_PCH_TYPE(dev_priv) == PCH_CNP ||
> > > +?????????? (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP && INTEL_PCH_TYPE(dev_priv)
> > > < PCH_DG1))
> > 
> > The check could be also moved to the helper.
> > 
> > > +???????????????cnp_irq_post_reset(dev_priv);
> > > ?}
> > > ?
> > > ?static void gen11_display_irq_reset(struct drm_i915_private *dev_priv)
> > > @@ -3104,15 +3123,9 @@ static void gen11_display_irq_reset(struct
> > > drm_i915_private *dev_priv)
> > > ????????if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
> > > ????????????????GEN3_IRQ_RESET(uncore, SDE);
> > > ?
> > > -???????/* Wa_14010685332:cnp/cmp,tgp,adp */
> > > ????????if (INTEL_PCH_TYPE(dev_priv) == PCH_CNP ||
> > > -?????????? (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP &&
> > > -??????????? INTEL_PCH_TYPE(dev_priv) < PCH_DG1)) {
> > > -???????????????intel_uncore_rmw(uncore, SOUTH_CHICKEN1,
> > > -??????????????????????????????? SBCLK_RUN_REFCLK_DIS,
> > > SBCLK_RUN_REFCLK_DIS);
> > > -???????????????intel_uncore_rmw(uncore, SOUTH_CHICKEN1,
> > > -??????????????????????????????? SBCLK_RUN_REFCLK_DIS, 0);
> > > -???????}
> > > +?????????? (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP && INTEL_PCH_TYPE(dev_priv)
> > > < PCH_DG1))
> > > +???????????????cnp_irq_post_reset(dev_priv);
> > > ?}
> > > ?
> > > ?static void gen11_irq_reset(struct drm_i915_private *dev_priv)
> > > @@ -3474,6 +3487,9 @@ static void spt_hpd_irq_setup(struct drm_i915_private
> > > *dev_priv)
> > > ????????ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
> > > ?
> > > ????????spt_hpd_detection_setup(dev_priv);
> > > +
> > > +???????if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
> > > +???????????????icp_hpd_irq_setup(dev_priv);
> > 
> > This doesn't look correct, icp_hpd_irq_setup() redoes the interrupt
> > setup done already earlier in this function and
> > spt_hpd_detection_setup() is probably also not correct on ICP+. Looks
> > like for ICP+ we need to call icp_hpd_irq_setup() instead of
> > spt_hpd_irq_setup(), but haven't checked in detail.
> 
> Could you please check :)? I don't work at Intel so you have far more access to
> this information then I do.?
> 
> FWIW the code -looks- mostly equivalent to me (SHOTPLUG_CTL_DDI and
> SHOTPLUG_CTL_TC seem to be equivalent registers to what's set in
> spt_hpd_irq_setup()), but the icelake point codepath enables an additional port,
> and changes an additional register called SHPD_FILTER_CNT.

The register definitions for SHOTPLUG_CTL_DDI wrt. PCH_PORT_HOTPLUG and
SHOTPLUG_CTL_TC wrt. PCH_PORT_HOTPLUG2 are different even though their
addresses match.

> I'll update it to use this in the next patch, but please definitely
> confirm this. I would very much like to avoid potentially breaking
> unrelated ICP systems with this.
> 
> > 
> > > ?}
> > > ?
> > > ?static u32 ilk_hotplug_enables(struct drm_i915_private *i915,
> > > @@ -3764,9 +3780,19 @@ static void gen8_de_irq_postinstall(struct
> > > drm_i915_private *dev_priv)
> > > ????????}
> > > ?}
> > > ?
> > > +static void icp_irq_postinstall(struct drm_i915_private *dev_priv)
> > > +{
> > > +???????struct intel_uncore *uncore = &dev_priv->uncore;
> > > +???????u32 mask = SDE_GMBUS_ICP;
> > > +
> > > +???????GEN3_IRQ_INIT(uncore, SDE, ~mask, 0xffffffff);
> > > +}
> > > +
> > > ?static void gen8_irq_postinstall(struct drm_i915_private *dev_priv)
> > > ?{
> > > -???????if (HAS_PCH_SPLIT(dev_priv))
> > > +???????if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
> > > +???????????????icp_irq_postinstall(dev_priv);
> > > +???????else if (HAS_PCH_SPLIT(dev_priv))
> > > ????????????????ibx_irq_postinstall(dev_priv);
> > > ?
> > > ????????gen8_gt_irq_postinstall(&dev_priv->gt);
> > > @@ -3775,13 +3801,6 @@ static void gen8_irq_postinstall(struct
> > > drm_i915_private *dev_priv)
> > > ????????gen8_master_intr_enable(dev_priv->uncore.regs);
> > > ?}
> > > ?
> > > -static void icp_irq_postinstall(struct drm_i915_private *dev_priv)
> > > -{
> > > -???????struct intel_uncore *uncore = &dev_priv->uncore;
> > > -???????u32 mask = SDE_GMBUS_ICP;
> > > -
> > > -???????GEN3_IRQ_INIT(uncore, SDE, ~mask, 0xffffffff);
> > > -}
> > > ?
> > > ?static void gen11_irq_postinstall(struct drm_i915_private *dev_priv)
> > > ?{
> > > -- 
> > > 2.29.2
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> 
> -- 
> Sincerely,
>    Lyude Paul (she/her)
>    Software Engineer at Red Hat
>    
> Note: I deal with a lot of emails and have a lot of bugs on my plate. If you've
> asked me a question, are waiting for a review/merge on a patch, etc. and I
> haven't responded in a while, please feel free to send me another email to check
> on my status. I don't bite!
>