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

[Chris Wilson]

Quoting Chris Wilson (2019-11-22 00:16:27)
> From: Andi Shyti <andi.shyti at intel.com>
> 
> Add three basic tests for rc6 power status:
> 
> 1. live_rc6_basic - simply checks if rc6 works when it's enabled
>    or stops when it's disabled.
> 
> 2. live_rc6_threshold - rc6 should not work when the evaluation
>    interval is less than the threshold and should work otherwise.
> 
> 3. live_rc6_busy - keeps the gpu busy and then goes in idle;
>    checks that we don't fall in rc6 when busy and that we do fall
>    in rc6 when idling.

One test worth extending is checking that live_rc6_busy works after a
reset, both per-engine and device.
-Chris