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Commit 19d0a572 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Defer enabling hangcheck to the first fake breadcrumb interrupt 



By deferring hangcheck to the fake breadcrumb interrupt, we can simply
the enabling procedure slightly - as by enabling the fake, we then
enable the hangcheck. By always enabling the hangcheck from each fake
interrupt (it will be a no-op for an already queued hangcheck), it will
make restoring the breadcrumbs after a reset simpler in the next patch.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170227205850.2828-3-chris@chris-wilson.co.uk
parent 56299fb7

drivers/gpu/drm/i915/intel_breadcrumbs.c

+18 −18
Original line number Diff line number Diff line
@@ -75,17 +75,6 @@ static void intel_breadcrumbs_hangcheck(unsigned long data) 
	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);



	/* Ensure that even if the GPU hangs, we get woken up.

	 *

	 * However, note that if no one is waiting, we never notice

	 * a gpu hang. Eventually, we will have to wait for a resource

	 * held by the GPU and so trigger a hangcheck. In the most

	 * pathological case, this will be upon memory starvation! To

	 * prevent this, we also queue the hangcheck from the retire

	 * worker.

	 */

	i915_queue_hangcheck(engine->i915);

}



static void intel_breadcrumbs_fake_irq(unsigned long data)
@@ -99,8 +88,21 @@ static void intel_breadcrumbs_fake_irq(unsigned long data) 
	 * every jiffie in order to kick the oldest waiter to do the

	 * coherent seqno check.

	 */

	if (intel_engine_wakeup(engine))

	if (!intel_engine_wakeup(engine))

		return;



	mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1);



	/* Ensure that even if the GPU hangs, we get woken up.

	 *

	 * However, note that if no one is waiting, we never notice

	 * a gpu hang. Eventually, we will have to wait for a resource

	 * held by the GPU and so trigger a hangcheck. In the most

	 * pathological case, this will be upon memory starvation! To

	 * prevent this, we also queue the hangcheck from the retire

	 * worker.

	 */

	i915_queue_hangcheck(engine->i915);

}



static void irq_enable(struct intel_engine_cs *engine)
@@ -179,14 +181,12 @@ static void __intel_breadcrumbs_enable_irq(struct intel_breadcrumbs *b) 
		b->irq_enabled = true;

	}



	if (!b->irq_enabled || use_fake_irq(b)) {

		mod_timer(&b->fake_irq, jiffies + 1);

		i915_queue_hangcheck(i915);

	} else {

	/* Ensure we never sleep indefinitely */

	if (!b->irq_enabled || use_fake_irq(b))

		mod_timer(&b->fake_irq, jiffies + 1);

	else

		mod_timer(&b->hangcheck, wait_timeout());

}

}



static void __intel_breadcrumbs_disable_irq(struct intel_breadcrumbs *b)

{