diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index f8aadc3c2124d01ca512f90ec1922c47497bc302..85fc2b1a124ad5e3fe72f97371c6fc3719ade829 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -563,6 +563,14 @@ static int init_ring_common(struct intel_engine_cs *ring) * also enforces ordering), otherwise the hw might lose the new ring * register values. */ I915_WRITE_START(ring, i915_gem_obj_ggtt_offset(obj)); + + /* WaClearRingBufHeadRegAtInit:ctg,elk */ + if (I915_READ_HEAD(ring)) + DRM_DEBUG("%s initialization failed [head=%08x], fudging\n", + ring->name, I915_READ_HEAD(ring)); + I915_WRITE_HEAD(ring, 0); + (void)I915_READ_HEAD(ring); + I915_WRITE_CTL(ring, ((ringbuf->size - PAGE_SIZE) & RING_NR_PAGES) | RING_VALID);