Re: [PATCH v2 3/3] drm/i915: Defer declaration of missed-interrupt until the waiter is asleep

Mika Kuoppala
2017-02-17T12:01:38Z

Chris Wilson <chris@chris-wilson.co.uk> writes:

> On Fri, Feb 17, 2017 at 01:35:15PM +0200, Mika Kuoppala wrote:
>> Chris Wilson <chris@chris-wilson.co.uk> writes:
>>
>> > If the waiter was currently running, assume it hasn't had a chance
>> > to process the pending interupt (e.g, low priority task on a loaded
>> > system) and wait until it sleeps before declaring a missed interrupt.
>> >
>> > References: https://bugs.freedesktop.org/show_bug.cgi?id=99816
>> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>> > Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
>> > ---
>> > drivers/gpu/drm/i915/intel_breadcrumbs.c | 9 +++++++++
>> > 1 file changed, 9 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
>> > index 4395b177493e..2ad29fb77b2d 100644
>> > --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
>> > +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
>> > @@ -45,6 +45,15 @@ static void intel_breadcrumbs_hangcheck(unsigned long data)
>> > return;
>> > }
>> >
>> > + /* If the waiter was currently running, assume it hasn't had a chance
>> > + * to process the pending interupt (e.g, low priority task on a loaded
>> > + * system) and wait until it sleeps before declaring a missed interrupt.
>> > + */
>> > + if (!intel_engine_wakeup(engine)) {
>>
>> But this will happen if there is waiter running, or that there is
>> no waiter at all.
>>
>> Don't we need to exclude the latter?
>
> We already exclude the latter by cancelling this timer above.

Got it now,
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre