drm/i915/ringbuffer: Exclude last 2 cachlines of ring on 845g
The 845g shares the errata with i830 whereby executing a command
within 2 cachelines of the end of the ringbuffer may cause a GPU hang.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index e25581a..f75806e 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1038,7 +1038,7 @@
* of the buffer.
*/
ring->effective_size = ring->size;
- if (IS_I830(ring->dev))
+ if (IS_I830(ring->dev) || IS_845G(ring->dev))
ring->effective_size -= 128;
return 0;