[Intel-gfx] [PATCH] drm/i915: Restore user forcewake references upon resume

[Daniel Vetter]

On Fri, Mar 14, 2014 at 5:07 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Fri, Mar 14, 2014 at 04:51:56PM +0100, Daniel Vetter wrote:
>> On Fri, Mar 14, 2014 at 08:47:14AM +0000, Chris Wilson wrote:
>> > Daniel stopped that we lose track of the user forcewake across suspend
>> > and resume, so hook up the code to restore it.
>> >
>> > Reported-by: Daniel Vetter <daniel.veter at ffwll.ch>
>> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> > Cc: Daniel Vetter <daniel.veter at ffwll.ch>
>>
>> Testcase: igt/drv_suspend/forcewake? Or have I screwed it up and the test
>> is bonkers?
>
> The testcase relies on the kernel exploding. We could try reading
> RING_CTL for a couple of seconds as see if returns 0.

Yeah, I somehow thought that we'd underrun the runtime pm refcount,
but we only underrun the forcewake refcounts. I guess that's a good
justification as any to WARN if the refcount is 0 and we attempt a
put.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch