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

From: Pavel Machek
Date: Tue Mar 21 2017 - 10:13:08 EST


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?

Is there something I can revert to get back to working system?

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

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