[Intel-gfx] [PATCH 06/18] drm/i915/breadcrumbs: Keep the fake irq armed across reset

[Chris Wilson]

Quoting Mika Kuoppala (2018-04-23 14:03:02)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> > @@ -148,6 +149,12 @@ static void intel_breadcrumbs_fake_irq(struct timer_list *t)
> >       if (!b->irq_armed)
> >               return;
> >  
> > +     /* If the user has disabled the fake-irq, restore the hangchecking */
> > +     if (!test_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings)) {
> > +             mod_timer(&b->hangcheck, wait_timeout());
> > +             return;
> > +     }
> > +
> 
> Looking at the cancel_fake_irq() now, which we still need to keep as
> sync, I think there is race introduce now as this can queue itself.
> 
> I think we want to also change the cancel_fake_irq() to do
> the bit clearing first, not last after the del_timer_syncs().

I see what you mean, but I think we want

	del_timer_sync(&b->fake_irq); // may queue b->hangcheck
	del_timer_sync(&b->hangcheck);
	clear_bit(engine->id. missed_irq_rings);

-Chris