[Intel-gfx] [PATCH 08/11] drm/i915/selftests: Flush the active callbacks

[Chris Wilson]

Before checking the current i915_active state for the asynchronous work
we submitted, flush any ongoing callback. This ensures that our sampling
is robust and does not sporadically fail due to bad timing as the work
is running on another cpu.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/intel_engine_pm.h  |  5 +++++
 drivers/gpu/drm/i915/gt/selftest_context.c | 19 +++++++++++++------
 drivers/gpu/drm/i915/intel_wakeref.h       | 14 ++++++++++++++
 3 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.h b/drivers/gpu/drm/i915/gt/intel_engine_pm.h
index 6db07bdd1eef..467475fce9c6 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.h
@@ -36,6 +36,11 @@ static inline void intel_engine_pm_put_async(struct intel_engine_cs *engine)
 	intel_wakeref_put_async(&engine->wakeref);
 }
 
+static inline void intel_engine_pm_unlock_wait(struct intel_engine_cs *engine)
+{
+	intel_wakeref_unlock_wait(&engine->wakeref);
+}
+
 void intel_engine_init__pm(struct intel_engine_cs *engine);
 
 #endif /* INTEL_ENGINE_PM_H */
diff --git a/drivers/gpu/drm/i915/gt/selftest_context.c b/drivers/gpu/drm/i915/gt/selftest_context.c
index 3586af636304..d1203b4c1409 100644
--- a/drivers/gpu/drm/i915/gt/selftest_context.c
+++ b/drivers/gpu/drm/i915/gt/selftest_context.c
@@ -48,20 +48,25 @@ static int context_sync(struct intel_context *ce)
 
 	mutex_lock(&tl->mutex);
 	do {
-		struct dma_fence *fence;
+		struct i915_request *rq;
 		long timeout;
 
-		fence = i915_active_fence_get(&tl->last_request);
-		if (!fence)
+		if (list_empty(&tl->requests))
 			break;
 
-		timeout = dma_fence_wait_timeout(fence, false, HZ / 10);
+		rq = list_last_entry(&tl->requests, typeof(*rq), link);
+		i915_request_get(rq);
+
+		timeout = i915_request_wait(rq, 0, HZ / 10);
 		if (timeout < 0)
 			err = timeout;
 		else
-			i915_request_retire_upto(to_request(fence));
+			i915_request_retire_upto(rq);
 
-		dma_fence_put(fence);
+		spin_lock_irq(&rq->lock);
+		spin_unlock_irq(&rq->lock);
+
+		i915_request_put(rq);
 	} while (!err);
 	mutex_unlock(&tl->mutex);
 
@@ -282,6 +287,8 @@ static int __live_active_context(struct intel_engine_cs *engine,
 		err = -EINVAL;
 	}
 
+	intel_engine_pm_unlock_wait(engine);
+
 	if (intel_engine_pm_is_awake(engine)) {
 		struct drm_printer p = drm_debug_printer(__func__);
 
diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
index ff4876093541..eeac3e7dfafe 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.h
+++ b/drivers/gpu/drm/i915/intel_wakeref.h
@@ -160,6 +160,20 @@ intel_wakeref_unlock(struct intel_wakeref *wf)
 	mutex_unlock(&wf->mutex);
 }
 
+/**
+ * intel_wakeref_unlock_wait: Wait until the active callback is complete
+ * @wf: the wakeref
+ *
+ * Waits for the active callback (under the @wf->mtuex) is complete.
+ */
+static inline void
+intel_wakeref_unlock_wait(struct intel_wakeref *wf)
+{
+	mutex_lock(&wf->mutex);
+	mutex_unlock(&wf->mutex);
+	flush_work(&wf->work);
+}
+
 /**
  * intel_wakeref_is_active: Query whether the wakeref is currently held
  * @wf: the wakeref
-- 
2.24.0