X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=drivers%2Fgpu%2Fdrm%2Fi915%2Fi915_irq.c;h=ae2b49969b995c0b1c7f7f76f65d2426ea003522;hb=ec6a890dfed7dd245beba5e5bcdfcffbd934c284;hp=b9fafe3b045bda5817047f2a5cde8a6fc1b58265;hpb=08d63aac436b2ad35d9e864b9ebb05bc8b9bb653;p=deliverable%2Flinux.git

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index b9fafe3b045b..ae2b49969b99 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1740,6 +1740,17 @@ void ironlake_irq_preinstall(struct drm_device *dev)
 		INIT_WORK(&dev_priv->rps_work, gen6_pm_rps_work);
 
 	I915_WRITE(HWSTAM, 0xeffe);
+	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);
+	}
 
 	/* XXX hotplug from PCH */