1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 2d6039b4571..3bd85f7e390 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -150,8 +150,6 @@ static int init_ring_common(struct intel_ring_buffer *ring)
         I915_WRITE_HEAD(ring, 0);
         ring->write_tail(ring, 0);
 
-        /* Initialize the ring. */
-        I915_WRITE_START(ring, obj->gtt_offset);
         head = I915_READ_HEAD(ring) & HEAD_ADDR;
 
         /* G45 ring initialization fails to reset head to zero */
@@ -177,6 +175,11 @@ static int init_ring_common(struct intel_ring_buffer *ring)
                 }
         }
 
+        /* Initialize the ring. This must happen _after_ we've cleared the ring
+         * registers with the above sequence (the readback of the HEAD registers
+         * also enforces ordering), otherwise the hw might lose the new ring
+         * register values. */
+        I915_WRITE_START(ring, obj->gtt_offset);
         I915_WRITE_CTL(ring,
                         ((ring->size - PAGE_SIZE) & RING_NR_PAGES)
                         | RING_REPORT_64K | RING_VALID);