If two requests are on the same ring, they are explicitly ordered by the HW. So, a submission fence is sufficient to ensure ordering when using the new GuC submission interface. Conversely, if two requests share a timeline and are on the same physical engine but different context this doesn't ensure ordering on the new GuC submission interface. So, a completion fence needs to be used to ensure ordering.
v2: (Daniele) - Don't delete spin lock
Signed-off-by: John Harrison John.C.Harrison@Intel.com Signed-off-by: Matthew Brost matthew.brost@intel.com --- drivers/gpu/drm/i915/i915_request.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index ef26724fe980..3ecdc9180d8f 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -432,6 +432,7 @@ void i915_request_retire_upto(struct i915_request *rq)
do { tmp = list_first_entry(&tl->requests, typeof(*tmp), link); + GEM_BUG_ON(!i915_request_completed(tmp)); } while (i915_request_retire(tmp) && tmp != rq); }
@@ -1380,6 +1381,9 @@ i915_request_await_external(struct i915_request *rq, struct dma_fence *fence) return err; }
+static int +i915_request_await_request(struct i915_request *to, struct i915_request *from); + int i915_request_await_execution(struct i915_request *rq, struct dma_fence *fence) @@ -1463,7 +1467,8 @@ i915_request_await_request(struct i915_request *to, struct i915_request *from) return ret; }
- if (is_power_of_2(to->execution_mask | READ_ONCE(from->execution_mask))) + if (!intel_engine_uses_guc(to->engine) && + is_power_of_2(to->execution_mask | READ_ONCE(from->execution_mask))) ret = await_request_submit(to, from); else ret = emit_semaphore_wait(to, from, I915_FENCE_GFP); @@ -1622,6 +1627,8 @@ __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_is_complete(prev)) { + bool uses_guc = intel_engine_uses_guc(rq->engine); + /* * The requests are supposed to be kept in order. However, * we need to be wary in case the timeline->last_request @@ -1632,7 +1639,8 @@ __i915_request_add_to_timeline(struct i915_request *rq) i915_seqno_passed(prev->fence.seqno, rq->fence.seqno));
- if (is_power_of_2(READ_ONCE(prev->engine)->mask | rq->engine->mask)) + if ((!uses_guc && is_power_of_2(READ_ONCE(prev->engine)->mask | rq->engine->mask)) || + (uses_guc && prev->context == rq->context)) i915_sw_fence_await_sw_fence(&rq->submit, &prev->submit, &rq->submitq);