[PATCH 1/4] drm/i915: Assert requests within a context are submitted in order

[Chris Wilson]

Check the flow of requests into the hardware to verify that are
submitted in order along their timeline.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 4 ++++
 drivers/gpu/drm/i915/i915_request.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 16a023ac4604..13941d1c0a4a 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1622,6 +1622,7 @@ static bool can_merge_rq(const struct i915_request *prev,
 	if (!can_merge_ctx(prev->context, next->context))
 		return false;
 
+	GEM_BUG_ON(i915_seqno_passed(prev->fence.seqno, next->fence.seqno));
 	return true;
 }
 
@@ -2142,6 +2143,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 				GEM_BUG_ON(last &&
 					   !can_merge_ctx(last->context,
 							  rq->context));
+				GEM_BUG_ON(last &&
+					   i915_seqno_passed(last->fence.seqno,
+							     rq->fence.seqno));
 
 				submit = true;
 				last = rq;
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index ca5361eb1f0b..35147df79655 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -737,6 +737,7 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
 	RCU_INIT_POINTER(rq->timeline, tl);
 	RCU_INIT_POINTER(rq->hwsp_cacheline, tl->hwsp_cacheline);
 	rq->hwsp_seqno = tl->hwsp_seqno;
+	GEM_BUG_ON(i915_request_completed(rq));
 
 	rq->rcustate = get_state_synchronize_rcu(); /* acts as smp_mb() */
 
@@ -1284,6 +1285,9 @@ __i915_request_add_to_timeline(struct i915_request *rq)
 	prev = to_request(__i915_active_fence_set(&timeline->last_request,
 						  &rq->fence));
 	if (prev && !i915_request_completed(prev)) {
+		GEM_BUG_ON(i915_seqno_passed(prev->fence.seqno,
+					     rq->fence.seqno));
+
 		if (is_power_of_2(prev->engine->mask | rq->engine->mask))
 			i915_sw_fence_await_sw_fence(&rq->submit,
 						     &prev->submit,
-- 
2.25.1