[Intel-gfx] [PATCH 07/19] drm/i915: add runtime put/get calls at the basic places

[Daniel Vetter]

On Thu, Dec 12, 2013 at 9:07 PM, Paulo Zanoni <przanoni at gmail.com> wrote:
>> This hunk here is the wrong thing to do: If we're suspended and the
>> hangcheck fires, we'll just delay it. But if we keep on being suspended
>> the hangcheck will fire at the normal recheck rate (but never do anything)
>> which wreaks utter havoc with deep sleep residency. The simples solution
>> would be to synchronously cancel the timer in the idle work (where we
>> already put the execbuf runtime ref) I think.
>>
>
> The problem is that if I do this, then we won't end up running the
> hangcheck (which we always run today), so we won't check for hangs,
> which is probably not good. I could add "i915_force_hangcheck" what
> would be called at intel_mark_idle if you would like, but I'm not too
> sure what are the downsides of doing this.

If the gpu is truly idle then there's no need to run the hangcheck any
more ... So I don't understand why we can't cancel it before we drop
the gpu-is-busy runtime pm reference.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch