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

Chris Wilson
2017-02-17T10:18:15Z

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)) {
+ mod_timer(&b->hangcheck, wait_timeout());
+ return;
+ }
+
DRM_DEBUG("Hangcheck timer elapsed... %s idle\n", engine->name);
set_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1);
--
2.11.0