[regression] Re: 4.11-rc0, thinkpad x220: GPU hang

[Pavel Machek]

On Mon 2017-03-06 12:23:41, Chris Wilson wrote:
> On Mon, Mar 06, 2017 at 01:10:48PM +0100, Pavel Machek wrote:
> > On Mon 2017-03-06 11:15:28, Chris Wilson wrote:
> > > On Mon, Mar 06, 2017 at 12:01:51AM +0100, Pavel Machek wrote:
> > > > Hi!
> > > > 
> > > > > > mplayer stopped working after a while. Dmesg says:
> > > > > > 
> > > > > > [ 3000.266533] cdc_ether 2-1.2:1.0 usb0: register 'cdc_ether' at
> > > > 
> > > > Now I'm pretty sure it is a regression in v4.11-rc0. Any ideas what to
> > > > try? Bisect will be slow and nasty :-(.
> > > 
> > > I came the conclusion that #99671 is the ring HEAD overtaking the TAIL,
> > > and under the presumption that your bug matches (as the symptoms do):
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > > index 4ffa35faff49..62e31a7438ac 100644
> > > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > > @@ -782,10 +782,10 @@ static void i9xx_submit_request(struct drm_i915_gem_request *request)
> > >  {
> > >         struct drm_i915_private *dev_priv = request->i915;
> > >  
> > > -       i915_gem_request_submit(request);
> > > -
> > >         GEM_BUG_ON(!IS_ALIGNED(request->tail, 8));
> > >         I915_WRITE_TAIL(request->engine, request->tail);
> > > +
> > > +       i915_gem_request_submit(request);
> > >  }
> > >  
> > >  static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs)
> > 
> > I applied it as:
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > index 91bc4ab..9c49c7a 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -1338,9 +1338,9 @@ static void i9xx_submit_request(struct drm_i915_gem_request *request)
> >  {
> >  	struct drm_i915_private *dev_priv = request->i915;
> >  
> > -	i915_gem_request_submit(request);
> > -
> >  	I915_WRITE_TAIL(request->engine, request->tail);
> > +
> > +	i915_gem_request_submit(request);
> >  }
> >  
> >  static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req,
> > 
> > Hmm. But your next mail suggest that it may not be smart to try to
> > boot it? :-).
> 
> Don't bother, it'll promptly hang.

Any news here? 4.11-rc5 is actually usable on the hardware (unlike
-rc1), not sure what changed.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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