Re: [Intel-gfx] [PATCH 2/2] drm/i915/gt: Warn if not in RC6 when GT is parked

[Tvrtko Ursulin]

On 11/10/2022 06:53, Dixit, Ashutosh wrote:
On Mon, 10 Oct 2022 20:29:23 -0700, Ashutosh Dixit wrote:

Some i915 modules implicitly assume that there is no user, kernel or
firmware activity after GT is parked. For example, PMU calculations are
incorrect if GT is not in RC6 when GT is parked (outside of the GT
wakeref). Therefore check and warn if GT is not in RC6 at the time of
parking the GT.

This patch has cause widespread dmesg_warn's in premerge CI so there is no
intention of merging this. It just proves that these assumptions in PMU
(for quantities such as frequency and RC6 residency) are incorrect and need
to be addressed.

Yeah this probably does not make sense since I am not sure if driver 
actually controls when hardware goes into RC6.

Regards,

Tvrtko


Thanks.
--
Ashutosh


@@ -123,6 +125,10 @@ static int __gt_park(struct intel_wakeref *wf)
                intel_display_power_put_async(i915, POWER_DOMAIN_GT_IRQ, 
wakeref);
        }

+       ret = intel_rc6_in_rc6(&gt->rc6, &in_rc6);
+       if (!ret && !in_rc6)
+               drm_warn_once(&i915->drm, "Parking, but GT is not in RC6!\n");
+
        return 0;
  }