drm/i915: Make closing request flush mandatory

For symmetry, simplicity and ensuring the request is always truly idle
upon its completion, always emit the closing flush prior to emitting the
request breadcrumb. Previously, we would only emit the flush if we had
started a user batch, but this just leaves all the other paths open to
speculation (do they affect the GPU caches or not?) With mm switching, a
key requirement is that the GPU is flushed and invalidated before hand,
so for absolute safety, we want that closing flush be mandatory.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180612105135.4459-1-chris@chris-wilson.co.uk

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
index 340a98c0c804..a4900091ae3d 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
@@ -199,7 +199,7 @@ static int gpu_set(struct drm_i915_gem_object *obj,
 
 	cs = intel_ring_begin(rq, 4);
 	if (IS_ERR(cs)) {
-		__i915_request_add(rq, false);
+		i915_request_add(rq);
 		i915_vma_unpin(vma);
 		return PTR_ERR(cs);
 	}
@@ -229,7 +229,7 @@ static int gpu_set(struct drm_i915_gem_object *obj,
 	reservation_object_add_excl_fence(obj->resv, &rq->fence);
 	reservation_object_unlock(obj->resv);
 
-	__i915_request_add(rq, true);
+	i915_request_add(rq);
 
 	return 0;
 }