[Intel-gfx] [PATCH v3] drm/i915: Enable WaProgramMgsrForCorrectSliceSpecificMmioReads for Gen9

[Chris Wilson]

Quoting Chris Wilson (2021-03-05 12:20:45)
> Quoting Tvrtko Ursulin (2021-03-05 09:23:02)
> > I am not sure if PC8 and DMC could also be involved from what Cooper was 
> > saying in a different thread. Maybe another CI run without the DMC, both 
> > ffs and fls. Another for limiting cstates.
> 
> Disabling the dmc leaves the display code in an inconsistent state so we
> don't complete a BAT run; but since the warnings are thrown during boot
> we can say that disabling the dmc does clear up the workaround issues on
> ehl/jsl:
> 
> https://intel-gfx-ci.01.org/tree/drm-tip/Trybot_7612/fi-ehl-2/boot0.txt
> https://intel-gfx-ci.01.org/tree/drm-tip/Trybot_7612/fi-jsl-1/boot0.txt

Fwiw, disabling the dmc and using fls for gen9 is not enough to avoid
the warnings though:

https://intel-gfx-ci.01.org/tree/drm-tip/Trybot_7614/fi-cfl-8109u/igt@i915_selftest@live@memory_region.html

So far only ffs works for gen9 mcr.
-Chris