[Intel-gfx] [PATCH] drm/i915: Gracefully handle obj not bound to GGTT in is_pin_display

[Mateo Lozano, Oscar]

> -----Original Message-----
> From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com]
> Sent: Thursday, May 15, 2014 2:34 PM
> To: Mateo Lozano, Oscar
> Cc: Daniel Vetter; intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH] drm/i915: Gracefully handle obj not bound to
> GGTT in is_pin_display
> 
> On Thu, May 15, 2014 at 01:14:54PM +0000, Mateo Lozano, Oscar wrote:
> > > > But looking at the code a better way should be:
> > > > 1. Create new bo, wrap it in a kms fb.
> > > > 2. Slap busy load onto that bo, e.g. reapeatedly fill it with the blitter.
> > > > 3. Enable evil interruptor (igt_fork_signal_helper).
> > > > 4. Submit pageflip
> > > >
> > > > -> Boom since the set_cache_level will block, get interrupted and
> > > > -> exit
> > > > early with -EINTR.
> > > >
> > > > Given sufficient overkill in 2. this should be 100% reliable to reproduce.
> >
> > As soon as I execbuffer to the bo, it gets a vma for the GGTT vm:
> >
> > 	vm = ctx->vm;
> > 	if (!USES_FULL_PPGTT(dev))
> > 		vm = &dev_priv->gtt.base;
> >
> > 	...
> >
> > 	/* Look up object handles */
> > 	ret = eb_lookup_vmas(eb, exec, args, vm, file);
> > 	if (ret)
> > 		goto err;
> >
> > And then it becomes impossible to reproduce the problem :( Is there
> > any other trick to make set_cache_level fail?
> 
> What if you make the pin_to_ggtt fail instead? Can you create an object that's
> too big for the ggtt?

Thanks Ville: that worked like a charm ;)