[Intel-gfx] [PATCH] drm/i915/pmu: Use GT parked for estimating RC6 while asleep

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-09-12 10:55:00)
> 
> On 12/09/2019 10:39, Chris Wilson wrote:
> > Quoting Tvrtko Ursulin (2019-09-12 10:20:39)
> >> Don't we end up doing the irqsave spinlock needlessly when !CONFIG_PM?
> > 
> > No, the intent is to serialise with i915_pmu_gt_parked and
> > i915_pmu_gt_unparked (and the GT awake state), which are independent of
> > CONFIG_PM.
> 
> Yes but with !CONFIG_PM we can always read the real counters and don't 
> need to do any additional magic. In fact code in i915_pmu_gt_(un)parked 
> could be ifdef-ed out for that case as well.

Oh, you mean if we didn't have to worry about runtime-pm at all for
mmio access. I was not thinking of that at all, just balancing parked vs
sample.
-Chris