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-rw-r--r--drivers/gpu/drm/i915/intel_ringbuffer.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index f8aadc3c2124d..85fc2b1a124ad 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);