[Intel-gfx] [PATCH] lib: Implement gem_sync() using WAIT

[Chris Wilson]

When synchronising to rendering, we only want to wait for it to complete
and avoid the cache-domain side-effects of SET_DOMAIN if possible. This
has the advantage of speeding up a few tests (and thereby making the
actual test more explicit in terms of kernel operations). Of course some
tests may be reliant on the side-effects...

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 lib/ioctl_wrappers.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
index dec45f1..000d394 100644
--- a/lib/ioctl_wrappers.c
+++ b/lib/ioctl_wrappers.c
@@ -371,12 +371,22 @@ void gem_set_domain(int fd, uint32_t handle,
  * @fd: open i915 drm file descriptor
  * @handle: gem buffer object handle
  *
- * This is a wrapper around gem_set_domain() which simply blocks for any
- * outstanding rendering to complete.
+ * This functions waits for outstanding rendering to complete.
  */
 void gem_sync(int fd, uint32_t handle)
 {
-	gem_set_domain(fd, handle, I915_GEM_DOMAIN_GTT, I915_GEM_DOMAIN_GTT);
+	struct drm_i915_gem_wait wait;
+
+	memset(&wait, 0, sizeof(wait));
+	wait.bo_handle = handle;
+	wait.timeout_ns =-1;
+	if (drmIoctl(fd, DRM_IOCTL_I915_GEM_WAIT, &wait) == 0) {
+		errno = 0;
+		return;
+	}
+
+	gem_set_domain(fd, handle,
+		       I915_GEM_DOMAIN_GTT, I915_GEM_DOMAIN_GTT);
 }
 
 uint32_t __gem_create(int fd, int size)
-- 
2.1.4