[PATCH] kick-once

[Chris Wilson]

---
 drivers/gpu/drm/i915/gt/intel_breadcrumbs.c       | 11 ++++++++---
 drivers/gpu/drm/i915/gt/intel_breadcrumbs.h       |  5 +++++
 drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h |  1 +
 drivers/gpu/drm/i915/gt/intel_engine_pm.c         |  1 +
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index 00918300f53f..7a915e856fe6 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -334,15 +334,20 @@ void intel_breadcrumbs_reset(struct intel_breadcrumbs *b)
 
 void intel_breadcrumbs_park(struct intel_breadcrumbs *b)
 {
-	/* Kick the work once more to drain the signalers */
+	if (!atomic_dec_and_test(&b->active))
+		return;
+
+	if (!READ_ONCE(b->irq_armed))
+		return;
+
+	/* Kick the work once more to drain the signalers, and disarm the irq */
 	irq_work_sync(&b->irq_work);
-	while (unlikely(READ_ONCE(b->irq_armed))) {
+	while (READ_ONCE(b->irq_armed) && !atomic_read(&b->active)) {
 		local_irq_disable();
 		signal_irq_work(&b->irq_work);
 		local_irq_enable();
 		cond_resched();
 	}
-	GEM_BUG_ON(!list_empty(&b->signalers));
 }
 
 void intel_breadcrumbs_free(struct intel_breadcrumbs *b)
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
index ed3d1deabfbd..c253e0d38db2 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
@@ -21,6 +21,11 @@ void intel_breadcrumbs_free(struct intel_breadcrumbs *b);
 void intel_breadcrumbs_reset(struct intel_breadcrumbs *b);
 void intel_breadcrumbs_park(struct intel_breadcrumbs *b);
 
+static inline void intel_breadcrumbs_unpark(struct intel_breadcrumbs *b)
+{
+	atomic_inc(&b->active);
+}
+
 static inline void
 intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine)
 {
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h
index a74bb3062bd8..2298d6b54d59 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h
@@ -31,6 +31,7 @@
 struct intel_breadcrumbs {
 	/* Not all breadcrumbs are attached to physical HW */
 	struct intel_engine_cs *irq_engine;
+	atomic_t active;
 
 	spinlock_t signalers_lock; /* protects the list of signalers */
 	struct list_head signalers;
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 499b09cb4acf..d74e748f677a 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -65,6 +65,7 @@ static int __engine_unpark(struct intel_wakeref *wf)
 	if (engine->unpark)
 		engine->unpark(engine);
 
+	intel_breadcrumbs_unpark(engine->breadcrumbs);
 	intel_engine_unpark_heartbeat(engine);
 	return 0;
 }
-- 
2.20.1