[Intel-gfx] [PATCH] drm/i915: Park faster to alleviate kept forcewake

[Chris Wilson]

Quoting Mika Kuoppala (2020-01-29 13:39:12)
> To avoid context corruption on some gens, we need to hold forcewake
> for long periods of time. This leads to increased energy expenditure
> for mostly idle workloads.
> 
> To combat the increased power consumption, park GPU more hastily.
> 
> As the HW isn't so quick to end up in rc6, this software mechanism
> supplements it. So we can apply it, across all gens.
> 
> Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
> Testcase: igt/i915_pm_rc6_residency/rc6-idle
> References: "Add RC6 CTX corruption WA"
> Cc: Stable <stable at vger.kernel.org>    # v4.19+
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

Seems to work and play nice with the older style of locking,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris