[Intel-gfx] [PATCH] drm/i915/d13: Fix unclaimed accesses while loading PIPEDMC-C/D

[Imre Deak]

On Wed, Aug 10, 2022 at 06:48:24AM +0300, Murthy, Arun R wrote:
> [...]
> > diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c
> > b/drivers/gpu/drm/i915/display/intel_dmc.c
> > index 00e18a4a5a5a4..6c35212c36256 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dmc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dmc.c
> > @@ -383,6 +383,30 @@ static void disable_all_event_handlers(struct
> > drm_i915_private *i915)
> >       }
> >  }
> >
> > +static void pipedmc_clock_gating_wa(struct drm_i915_private *i915, bool
> > +enable) {
> > +     enum pipe pipe;
> > +
> > +     if (DISPLAY_VER(i915) != 13)
> > +             return;
> > +
> This function will be called from bxt_display_core_init() as well.

Yes, this function is called whenever the DMC firmware needs to be
loaded and initialized/uninitialized. 

> Do we need this WA for bxt as well?

The above display version check makes sure that the WA is only applied
on relevant platforms. For BXT DISPLAY_VER()==9 (for GLK it's 10), for
DG2/ADLP DISPLAY_VER()=13.

--Imre