[Intel-gfx] [PATCH] drm/i915: Mark semaphores as complete on unsubmit out if payload was started

[Chris Wilson]

Avoid charging us for the presumed busywait if the request was preempted
after successfully using semaphores to reduce inter-engine latency.

References: ca6e56f654e7 ("drm/i915: Disable semaphore busywaits on saturated systems")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_request.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index bed213148cbb..4e6a7f37fffc 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -509,6 +509,10 @@ void __i915_request_unsubmit(struct i915_request *request)
 	/* Transfer back from the global per-engine timeline to per-context */
 	move_to_timeline(request, request->timeline);
 
+	/* We've already spun, don't charge on resubmitting. */
+	if (request->sched.semaphores && i915_request_started(request))
+		request->sched.semaphores = 0;
+
 	/*
 	 * We don't need to wake_up any waiters on request->execute, they
 	 * will get woken by any other event or us re-adding this request
-- 
2.20.1