[Intel-gfx] [PATCH v3 4/7] drm/i915: add support for checking if we hold an RPM reference

[Chris Wilson]

On Thu, Nov 12, 2015 at 07:50:09PM +0200, Imre Deak wrote:
> On to, 2015-11-12 at 17:04 +0000, Chris Wilson wrote:
> > As it stands since we don't actually cancel the hangcheck when we
> drop
> > the rpm wakelock in intel_mark_idle() it can very well come to pass
> > that
> > we execute this whilst the device is asleep. However, if the device
> > is
> > alseep, we now that we are no longer executing.
> 
> But how could this run while asleep, since we flush the work in the
> runtime suspend handler before turning off the HW? But even if it can't
> run your idea would be clearer imo..

We shouldn't be flushing the hangcheck worker there. That's a leaky
abstraction attempting to paper over something that shouldn't have been
a problem in the first place. Note that there is a similar issue with
the existing request waiters that currently may race against
intel_mark_idle().
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre