[PATCH i915 v6 2/2] i915: wait for fence in prepare_plane_fb

[Alex Goins]

In intel_prepare_plane_fb, if fb is backed by dma-buf, wait for exclusive
fence

v2: First commit
v3: Remove object_name_lock acquire
    Move wait from intel_atomic_commit() to intel_prepare_plane_fb()
v4: Wait only on exclusive fences, interruptible with no timeout
v5: Style tweaks to more closely match rest of file
v6: Properly handle interrupted waits

Signed-off-by: Alex Goins <agoins at nvidia.com>
---
 drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bacf336..604186b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13347,6 +13347,17 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	if (!obj)
 		return 0;
 
+	/* For framebuffer backed by dmabuf, wait for fence */
+	if (obj->base.dma_buf) {
+		ret = reservation_object_wait_timeout_rcu(obj->base.dma_buf->resv,
+							  false, true,
+							  MAX_SCHEDULE_TIMEOUT);
+		if (ret == -ERESTARTSYS)
+			return ret;
+
+		WARN_ON(ret < 0);
+	}
+
 	mutex_lock(&dev->struct_mutex);
 
 	if (plane->type == DRM_PLANE_TYPE_CURSOR &&
-- 
1.9.1