[Intel-gfx] [PATCH] drm/i915/selftests: add basic selftests for rc6

[Chris Wilson]

Quoting Andi Shyti (2020-02-05 18:40:55)
> Hi Mika,
>
> > I have a faint memory that the interval was not always 1.28us
> > but gen dependant.
> 
> 1.28 is the incremental step and I haven't seen any different
> value in the docs. Have you?

The rc6 residency counter does flip over to a different clock on
vlv/bsw. But the lack of information abounds, and I haven't seen
anything that suggests these registers are anything but units of
1280ns. If we get to the point where we can differentiate between 833ns
or 1280ns that will be very impressive.
-Chris