diff --git a/[refs] b/[refs]
index d6555d955ac9..4ef66ced4861 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cc391bbbddd16c36dabcb9f4a26500a2973a7108
+refs/heads/master: c54e59046c825266ca0decdac47fcfcf902b6cd6
diff --git a/trunk/drivers/gpu/drm/i915/i915_drv.c b/trunk/drivers/gpu/drm/i915/i915_drv.c
index f5b505a5b81e..f7aef97290bc 100644
--- a/trunk/drivers/gpu/drm/i915/i915_drv.c
+++ b/trunk/drivers/gpu/drm/i915/i915_drv.c
@@ -1264,6 +1264,10 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
 	} \
 	if (IS_GEN5(dev_priv->dev)) \
 		ilk_dummy_write(dev_priv); \
+	if (IS_HASWELL(dev_priv->dev) && (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
+		DRM_ERROR("Unknown unclaimed register before writing to %x\n", reg); \
+		I915_WRITE_NOTRACE(GEN7_ERR_INT, ERR_INT_MMIO_UNCLAIMED); \
+	} \
 	if (IS_VALLEYVIEW(dev_priv->dev) && IS_DISPLAYREG(reg)) { \
 		write##y(val, dev_priv->regs + reg + 0x180000);		\
 	} else {							\