From bae4fcd2c7b778a3f69e03e244221cd4932b8f67 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Mon, 30 Jun 2014 09:53:43 -0700 Subject: [PATCH] drm/i915/bdw: poll semaphores As Ville points out, it's possible/probable we don't actually need this. Potentially, this validates the letter of the spec, and not the spirit. Ville: > I discussed this on irc w/ Ben, and I was suggesting we don't need to > poll. Polling apparently can be used as a workaround for certain > hardware issues, but it looks like those issues shouldn't affect us, > for the momemnt at least. So my suggestion was to try w/o polling > first (since there could be some power cost to polling) and add the > poll bit if problems arise. Rodrigo: Spec suggests this as an W/A for GT3. However semaphores didn't worked in my BDW GT2 on Signal Mode. So pool mode is definitely needed. Reviewed-by: Rodrigo Vivi Tested-by: Rodrigo Vivi Signed-off-by: Ben Widawsky Signed-off-by: Rodrigo Vivi Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_ringbuffer.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 88196808cc40..e18ed05dc0d5 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -847,6 +847,7 @@ gen8_ring_sync(struct intel_engine_cs *waiter, intel_ring_emit(waiter, MI_SEMAPHORE_WAIT | MI_SEMAPHORE_GLOBAL_GTT | + MI_SEMAPHORE_POLL | MI_SEMAPHORE_SAD_GTE_SDD); intel_ring_emit(waiter, seqno); intel_ring_emit(waiter, -- 2.30.2