Re: [Intel-gfx] [PATCH v5 6/6] drm/i915/psr: Implement Display WA #1136

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Tue, 2023-03-28 at 14:26 +0300, Ville Syrjälä wrote:
> On Wed, Mar 22, 2023 at 12:34:12PM +0200, Jouni Högander wrote:
> > Implement Display WA #1136 for SKL/BXT.
> 
> 
> > 
> > Bspec: 21664
> > 
> > Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_psr.c     | 17
> > +++++++++++++++++
> >  drivers/gpu/drm/i915/display/skl_watermark.c |  5 -----
> >  2 files changed, 17 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > b/drivers/gpu/drm/i915/display/intel_psr.c
> > index b53c71c06105..24c3f75bb9d8 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1950,6 +1950,7 @@ void intel_psr_pre_plane_update(struct
> > intel_atomic_state *state,
> >  /*
> >   * Wa_16013835468
> >   * Wa_14015648006
> > + * Display WA #1136: skl, bxt
> >   */
> >  static void wm_optimization_wa(struct intel_dp *intel_dp,
> >                            const struct intel_crtc_state
> > *crtc_state)
> > @@ -1957,6 +1958,17 @@ static void wm_optimization_wa(struct
> > intel_dp *intel_dp,
> >         struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> >         bool set_wa_bit = false;
> >  
> > +       /*
> > +        * Display WA #1136: skl, bxt
> > +        * skl/bxt do not have chicken bit: disable PSR
> > +        */
> > +       if (DISPLAY_VER(dev_priv) <= 9) {
> 
> If we limit the chicken bit to icl+ for now then this stuff
> needs to be 'DISPLAY_VER < 11'.
> 

Ok, I will change this.

> 
> > +               if (crtc_state->wm_level_disabled &&
> > +                   intel_dp->psr.enabled)
> > +                       intel_psr_disable_locked(intel_dp);
> 
> This seems like it should be part of the pre_plane_update psr
> disable.

See my comment about intel_update_watermarks being called in
intel_display.c:intel_pre_plane_update and provide me your opinion
there.

> 
> > +               return;
> > +       }
> > +
> >         /* Wa_14015648006 */
> >         if (IS_MTL_DISPLAY_STEP(dev_priv, STEP_A0, STEP_B0) ||
> >             IS_DISPLAY_VER(dev_priv, 11, 13))
> > @@ -1999,12 +2011,17 @@ static void
> > _intel_psr_post_plane_update(const struct intel_atomic_state
> > *state,
> >                 keep_disabled |= psr->sink_not_reliable;
> >                 keep_disabled |= !crtc_state->active_planes;
> >  
> > +               /* Display WA #1136: skl, bxt */
> > +               keep_disabled |= DISPLAY_VER(dev_priv) <= 9 &&
> > +                       crtc_state->wm_level_disabled;
> > +
> >                 if (!psr->enabled && !keep_disabled)
> >                         intel_psr_enable_locked(intel_dp,
> > crtc_state);
> >  
> >                 /*
> >                  * Wa_16013835468
> >                  * Wa_14015648006
> > +                * Display WA #1136: skl, bxt
> >                  */
> >                 wm_optimization_wa(intel_dp, crtc_state);
> >  
> > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c
> > b/drivers/gpu/drm/i915/display/skl_watermark.c
> > index afb751c024ba..ced61da8b496 100644
> > --- a/drivers/gpu/drm/i915/display/skl_watermark.c
> > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c
> > @@ -2278,11 +2278,6 @@ static int skl_wm_check_vblank(struct
> > intel_crtc_state *crtc_state)
> >          */
> >         crtc_state->wm_level_disabled = level < i915-
> > >display.wm.num_levels - 1;
> >  
> > -       /*
> > -        * FIXME also related to skl+ w/a 1136 (also unimplemented
> > as of
> > -        * now) perhaps?
> > -        */
> > -
> >         for (level++; level < i915->display.wm.num_levels; level++)
> > {
> >                 enum plane_id plane_id;
> >  
> > -- 
> > 2.34.1
>