drm/i915: add set_tail hook in struct intel_ring_buffer

This is prepared for video codec ring buffer on Sandybridge. It is
needed to read/write more than one register to move the tail pointer of
the video codec ring on Sandybridge.

Signed-off-by: Xiang, Haihao <haihao.xiang@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 5603d6e945e9..7bd571c796ae 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -48,6 +48,8 @@ struct  intel_ring_buffer {
                         struct intel_ring_buffer *ring);
         unsigned int    (*get_tail)(struct drm_device *dev,
                         struct intel_ring_buffer *ring);
+        void            (*set_tail)(struct drm_device *dev,
+                        u32 value);
         unsigned int    (*get_active_head)(struct drm_device *dev,
                         struct intel_ring_buffer *ring);
         void            (*advance_ring)(struct drm_device *dev,