[Intel-gfx] [PATCH] drm/i915/selftests: Wait only on the expected barrier

[Chris Wilson]

Wait on only the last request on the kernel_context after emitting a
barrier so that we do not wait for everything in general and by doing so
cause an accidental emission of the barrier!

Bugzilla; https://bugs.freedesktop.org/show_bug.cgi?id=112405
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 .../drm/i915/gt/selftest_engine_heartbeat.c   | 24 ++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c
index 0b1148cf3f61..5227e79204a5 100644
--- a/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c
+++ b/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c
@@ -11,6 +11,28 @@
 #include "intel_gt_requests.h"
 #include "i915_selftest.h"
 
+static int timeline_sync(struct intel_timeline *tl)
+{
+	struct dma_fence *fence;
+	long timeout;
+
+	fence = i915_active_fence_get(&tl->last_request);
+	if (!fence)
+		return 0;
+
+	timeout = dma_fence_wait_timeout(fence, true, HZ / 2);
+	dma_fence_put(fence);
+	if (timeout < 0)
+		return timeout;
+
+	return 0;
+}
+
+static int engine_sync_barrier(struct intel_engine_cs *engine)
+{
+	return timeline_sync(engine->kernel_context->timeline);
+}
+
 struct pulse {
 	struct i915_active active;
 	struct kref kref;
@@ -90,7 +112,7 @@ static int __live_idle_pulse(struct intel_engine_cs *engine,
 
 	GEM_BUG_ON(!llist_empty(&engine->barrier_tasks));
 
-	if (intel_gt_retire_requests_timeout(engine->gt, HZ / 5)) {
+	if (engine_sync_barrier(engine)) {
 		struct drm_printer m = drm_err_printer("pulse");
 
 		pr_err("%s: no heartbeat pulse?\n", engine->name);
-- 
2.24.0