Re: [PATCH v2] drm/i915/fbc: Apply wa_15018326506

["Govindapillai, Vinod" <vinod.govindapillai@intel.com>]

On Fri, 2025-11-14 at 09:59 -0300, Gustavo Sousa wrote:
> Quoting Vinod Govindapillai (2025-11-11 09:46:06-03:00)
> > Disable FBC in bmg as per the wa recommendation.
> > 
> > v2: use the bmg platform instead of a specific stepping
> > 
> > Bspec: 74212
> > Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
> > ---
> > drivers/gpu/drm/i915/display/intel_display_wa.c |  2 ++
> > drivers/gpu/drm/i915/display/intel_display_wa.h |  1 +
> > drivers/gpu/drm/i915/display/intel_fbc.c        | 10 ++++++++++
> > 3 files changed, 13 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.c
> > b/drivers/gpu/drm/i915/display/intel_display_wa.c
> > index e38e5e87877c..b2e71fa61c0a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_wa.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_wa.c
> > @@ -70,6 +70,8 @@ bool __intel_display_wa(struct intel_display
> > *display, enum intel_display_wa wa,
> >                 return DISPLAY_VER(display) == 13;
> >         case INTEL_DISPLAY_WA_22014263786:
> >                 return IS_DISPLAY_VERx100(display, 1100, 1400);
> > +        case INTEL_DISPLAY_WA_15018326506:
> > +                return display->platform.battlemage;
> >         default:
> >                 drm_WARN(display->drm, 1, "Missing Wa number:
> > %s\n", name);
> >                 break;
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.h
> > b/drivers/gpu/drm/i915/display/intel_display_wa.h
> > index 3644e8e2b724..f648b00cb97d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_wa.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_wa.h
> > @@ -26,6 +26,7 @@ enum intel_display_wa {
> >         INTEL_DISPLAY_WA_16025573575,
> >         INTEL_DISPLAY_WA_14011503117,
> >         INTEL_DISPLAY_WA_22014263786,
> > +        INTEL_DISPLAY_WA_15018326506,
> > };
> > 
> > bool __intel_display_wa(struct intel_display *display, enum
> > intel_display_wa wa, const char *name);
> > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c
> > b/drivers/gpu/drm/i915/display/intel_fbc.c
> > index a1e3083022ee..16cd99db2978 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> > @@ -1521,6 +1521,16 @@ static int intel_fbc_check_plane(struct
> > intel_atomic_state *state,
> >                 return 0;
> >         }
> > 
> > +        /*
> > +         * wa_15018326506:
> 
> Drive-by nitpick comment: The most common usage is Wa_* instead of
> wa_*.
> 
>     $ git grep -hio '\<wa_[0-9]\+' -- drivers/gpu/drm/xe
> drivers/gpu/drm/i915 | sed 's/\([Ww][aA]_\).*/\1/' | sort | uniq -c
>          22 wa_
>         317 Wa_
>           3 WA_
> 
> This could be fixed while applying, since it is just a comment fix.
> 
> Also, I would wait for the workaround to be formalized as permanent
> workaround before merging this.
> 
> --
> Gustavo Sousa

Okay.. I can change the comment.

About the merge, got the go ahead to merge this. 

Thanks
Vinod
> 
> > +         * Fixes: Underrun during media decode
> > +         * Workaround: Do not enable FBC
> > +         */
> > +        if (intel_display_wa(display, 15018326506)) {
> > +                plane_state->no_fbc_reason = "Wa_15018326506";
> > +                return 0;
> > +        }
> > +
> >         /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
> >         if (intel_display_vtd_active(display) &&
> >             (display->platform.skylake || display-
> > >platform.broxton)) {
> > -- 
> > 2.43.0
> >