[Intel-gfx] [PATCH i-g-t] pm_rps: Extended testcases with checking PMINTRMSK register value

[Chris Wilson]

Quoting Chris Wilson (2017-08-21 10:53:36)
> Quoting Arkadiusz Hiler (2017-08-21 10:42:25)
> > On Mon, Aug 21, 2017 at 08:05:58AM +0000, Dec, Katarzyna wrote:
> > > I understand we do not want to check registers in IGT tests. What
> > > about reading interrupt masks from debugfs (i915_frequency_info).
> > 
> > Hey Kasia
> > 
> > It would be pretty much the same thing, but instead of us reading the
> > PMINTRMASK directly we would ask the kernel to do that on our behalf.
> > 
> > That would just hide register read, not get rid of it.
> > 
> > 
> > I think you are missing the point. The idea is that we do not want to
> > test details of in-kernel implementation, not ban the register reads
> > completely.
> > 
> > Reading register directly, especially just to make sure that the kernel
> > set something correctly is a good indicator that we are trying to do
> > just that - test the internal details.
> > 
> > > Would that be better approach? You guys suggested to get interested in
> > > kselftests for having such checks, but I am afraid that it could be
> > > too much job and we have too few hands to work.
> > 
> > How much of an effort would the kselftest be, since it seems that you did some
> > investigation already?
> 
> It doesn't even require a whole selftest, just something like
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 448e71af4772..e83b67fe0354 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -7733,7 +7733,8 @@ void intel_suspend_gt_powersave(struct drm_i915_private *dev_priv)
>         if (cancel_delayed_work_sync(&dev_priv->rps.autoenable_work))
>                 intel_runtime_pm_put(dev_priv);
>  
> -       /* gen6_rps_idle() will be called later to disable interrupts */
> +       WARN_ON(I915_READ(GEN6_PMINTRMSK) !=
> +               gen6_sanitize_rps_pm_mask(dev_priv, ~0));
>  }

Wrong spot. We actually need a call from
intel_runtime_pm_disable_interrupts.
-Chris