+ if (IS_GEN6(dev)) {
+ /* Workaround stalls observed on Sandy Bridge GPUs by
+ * making the blitter command streamer generate a
+ * write to the Hardware Status Page for
+ * MI_USER_INTERRUPT. This appears to serialize the
+ * previous seqno write out before the interrupt
+ * happens.
+ */
+ I915_WRITE(GEN6_BLITTER_HWSTAM, ~GEN6_BLITTER_USER_INTERRUPT);
+ I915_WRITE(GEN6_BSD_HWSTAM, ~GEN6_BSD_USER_INTERRUPT);
+ }