[Intel-gfx] [PATCH] drm/i915: Don't skip request retirement if the active list is empty

[Jani Nikula]

On Thu, 28 May 2015, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Thu, May 28, 2015 at 06:32:36PM +0300, ville.syrjala at linux.intel.com wrote:
>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> 
>> Apparently we can have requests even if though the active list is empty,
>> so do the request retirement regardless of whether there's anything
>> on the active list.
>> 
>> The way it happened here is that during suspend intel_ring_idle()
>> notices the olr hanging around and then proceeds to get rid of it by
>> adding a request. However since there was nothing on the active lists
>> i915_gem_retire_requests() didn't clean those up, and so the idle work
>> never runs, and we leave the GPU "busy" during suspend resulting in a
>> WARN later.
>
> Whlist I agree (I use list_empty(&ring->request_list);) I strongly
> suspect something (i.e. execlists) isn't managing the active_list
> correctly. Pretty much the only thing that can generate a request
> without an object (and so avoid touching the active_list) is a CS flip,
> and I doubt you are using those...
>
> Anyway,
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: stable at vger.linux.org

Pushed to drm-intel-fixes, thanks for the patch and review.

BR,
Jani.


> -Chris
>
> -- 
> Chris Wilson, Intel Open Source Technology Centre
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-- 
Jani Nikula, Intel Open Source Technology Center