From: John Harrison <[email protected]> The call to enable signaling was occuring after the request had been sent to the GuC for execution on the hardware. That means that it is possible for the request to actually complete before the code to enable signaling has executed.
Potentially that means the request could be signalled before anyone is ready to receive the signal and thus lead to a deadlock where the driver is now waiting for a signal that will never arrive because it has already missed it. Certainly it will lead to the BUG in nested_enable_signaling() firing complaining that the request has already been signaled. This patch reverses the order. Signaling is now enabled before sending the request to the GuC. Signed-off-by: John Harrison <[email protected]> --- drivers/gpu/drm/i915/i915_guc_submission.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index ff82f0561ec1..edf29758f35a 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -721,7 +721,6 @@ static bool i915_guc_dequeue(struct intel_engine_cs *engine) } i915_gem_request_assign(&port->request, last); - nested_enable_signaling(last); port++; } @@ -749,6 +748,7 @@ static bool i915_guc_dequeue(struct intel_engine_cs *engine) } #endif } + nested_enable_signaling(rq); i915_guc_submit(rq); trace_i915_gem_request_in(rq, port - engine->execlist_port); last = rq; @@ -758,7 +758,6 @@ static bool i915_guc_dequeue(struct intel_engine_cs *engine) } if (submit) { i915_gem_request_assign(&port->request, last); - nested_enable_signaling(last); engine->execlist_first = rb; } out: -- 2.13.0 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
