[Intel-gfx] [PATCH] drm/i915: Assert the engine has finished the seqno on unsubmission

[Chris Wilson]

Assert that we do not try to unsubmit a completed request, as should we
try to resubmit it later, the ring is already past the request's
breadcrumb and the breadcrumb will not be updated.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_request.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 9b02310307fc..7192521e3d10 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -652,6 +652,8 @@ void __i915_gem_request_unsubmit(struct drm_i915_gem_request *request)
 	 */
 	GEM_BUG_ON(!request->global_seqno);
 	GEM_BUG_ON(request->global_seqno != engine->timeline->seqno);
+	GEM_BUG_ON(i915_seqno_passed(intel_engine_get_seqno(engine),
+				     request->global_seqno));
 	engine->timeline->seqno--;
 
 	/* We may be recursing from the signal callback of another i915 fence */
-- 
2.15.1