On Thu, Jul 21, 2016 at 07:57:39AM +0100, Chris Wilson wrote: > As the interrupt wakeup counter only increments when we have a waiter, > before testing to see if that counter is unchanged we have to first > check that we do expect it to change (i.e. we have a waiter). > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_irq.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c > index 7104dc1463eb..45afcdfe89b1 100644 > --- a/drivers/gpu/drm/i915/i915_irq.c > +++ b/drivers/gpu/drm/i915/i915_irq.c > @@ -3062,7 +3062,9 @@ static unsigned long kick_waiters(struct intel_engine_cs *engine) > struct drm_i915_private *i915 = engine->i915; > unsigned long irq_count = READ_ONCE(engine->breadcrumbs.irq_wakeups); > > - if (engine->hangcheck.user_interrupts == irq_count && > + rcu_read_lock(); > + if (intel_engine_wakeup(engine) && > + engine->hangcheck.user_interrupts == irq_count && Sigh. Completely nerfs the detection of stuck waiters. Should be if (engine->hangcheck.user_interrupts == irq_count && intel_engine_wakeup(engine) && The test itself doesn't imply a missed interrupt either, there be a valid long lived batch causing a delay in the waiter. We can do better if we allow ourselves to take a spinlock here. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
