[Intel-gfx] [PATCH] drm/i915/selftests: Wait until we start timeslicing after a submit

[Chris Wilson]

If we submit, we do not start timeslicnig until we process the CS event
that marks the start of the context running on HW. So in the selftest,
be sure to wait until we have processed the pending events before
asserting that timeslicing has begun.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/selftest_lrc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 985d4041d929..9e02917695b1 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -1244,7 +1244,11 @@ static int live_timeslice_queue(void *arg)
 		if (err)
 			goto err_rq;
 
-		intel_engine_flush_submission(engine);
+		/* Wait until we ack the release_queue and start timeslicing */
+		do {
+			intel_engine_flush_submission(engine);
+		} while (READ_ONCE(engine->execlists.pending[0]));
+
 		if (!READ_ONCE(engine->execlists.timer.expires) &&
 		    !i915_request_completed(rq)) {
 			struct drm_printer p =
-- 
2.20.1