[Intel-gfx] [PATCH] drm/i915: Cancel all ready but queued requests when wedging

[Michał Winiarski]

On Fri, Sep 15, 2017 at 05:59:30PM +0100, Chris Wilson wrote:
> Quoting Chris Wilson (2017-09-15 17:49:16)
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> > index abf171c3cb9c..04fc50c993bf 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> > @@ -306,6 +306,14 @@ struct intel_engine_cs {
> >         void            (*schedule)(struct drm_i915_gem_request *request,
> >                                     int priority);
> >  
> > +       /*
> > +        * Cancel all requests on the hardware, or queued for execution.
> > +        *
> > +        * This is called under the engine->timeline->lock when marking
> > +        * the device as wedged.
> > +        */
> > +       void            (*cancel_all_requests)(struct intel_engine_cs *engine);
> 
> cancel_all_requests is a bit too broad, could just shorten it to
> cancel_requests with the doc explaining that we only cancel the requests
> that have been submitted to the engine (not the not-yet-ready requests
> still floating in the aether).
> -Chris

I agree.

Note, that we're still doing part of the work directly in submit_notify:

	/* Mark all executing requests as skipped */
	list_for_each_entry(request, &engine->timeline->requests, link) {
		GEM_BUG_ON(!request->global_seqno);
		if (!i915_gem_request_completed(request))
			dma_fence_set_error(&request->fence, -EIO);
	}

Perhaps it would be cleaner if we could extract that (cancel_requests_inflight?)
and us it as a cancel_requests for legacy ringbuf? (then just call into that in
cancel_requests for execlists)
Thoughts?

-Michał