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

[Chiou, Cooper]

After switched to ffs from fls in "patch v5"(https://patchwork.freedesktop.org/series/81764/#rev7), now CI result is PASS no regression in wa_verify warning.

@Chen, Rong
Could you please run “phoronix-test-suite.supertuxkart.1024x768.Fullscreen.Ultimate.1.GranParadisoIsland.frames_per_second” with this latest patch v5 on test box to see if any performance impact. Thanks,

Best Regards,
Cooper

> 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
> -Chris