diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 10aec0e..703a08a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -665,6 +665,17 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 		DRM_DEBUG_DRIVER("PCH transcoder A underrun interrupt\n");
 }
 
+static void err_int_handler(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	u32 err_int = I915_READ(GEN7_ERR_INT);
+
+	if (err_int & ERR_INT_POISON)
+		DRM_ERROR("Poison interrupt\n");
+
+	I915_WRITE(GEN7_ERR_INT, err_int);
+}
+
 static void serr_int_handler(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -715,16 +726,33 @@ static irqreturn_t ivybridge_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 de_iir, gt_iir, de_ier, pm_iir, sde_ier;
+	u32 de_iir, gt_iir, de_ier, pm_iir, sde_ier, de_imr;
 	irqreturn_t ret = IRQ_NONE;
 	int i;
 
 	atomic_inc(&dev_priv->irq_received);
 
+	/* We get interrupts on unclaimed registers, so check for this before we
+	 * do any I915_{READ,WRITE}. */
+	if (IS_HASWELL(dev) &&
+	    (I915_READ_NOTRACE(FPGA_DBG) & FPGA_DBG_RM_NOCLAIM)) {
+		DRM_ERROR("Unclaimed register before interrupt\n");
+		I915_WRITE_NOTRACE(FPGA_DBG, FPGA_DBG_RM_NOCLAIM);
+	}
+
 	/* disable master interrupt before clearing iir  */
 	de_ier = I915_READ(DEIER);
 	I915_WRITE(DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
 
+	/* On Haswell, also mask ERR_INT because we don't want to risk
+	 * generating "unclaimed register" interrupts from inside the interrupt
+	 * handler. */
+	de_imr = I915_READ(DEIMR);
+	if (IS_HASWELL(dev)) {
+		I915_WRITE(DEIMR, de_imr | DE_ERR_INT_IVB);
+		POSTING_READ(DEIMR);
+	}
+
 	sde_ier = I915_READ(SDEIER);
 	I915_WRITE(SDEIER, 0);
 	POSTING_READ(SDEIER);
@@ -738,6 +766,9 @@ static irqreturn_t ivybridge_irq_handler(int irq, void *arg)
 
 	de_iir = I915_READ(DEIIR);
 	if (de_iir) {
+		if (de_iir & DE_ERR_INT_IVB)
+			err_int_handler(dev);
+
 		if (de_iir & DE_AUX_CHANNEL_A_IVB)
 			dp_aux_irq_handler(dev);
 
@@ -775,6 +806,11 @@ static irqreturn_t ivybridge_irq_handler(int irq, void *arg)
 		ret = IRQ_HANDLED;
 	}
 
+	if (IS_HASWELL(dev)) {
+		I915_WRITE(DEIMR, de_imr);
+		POSTING_READ(DEIMR);
+	}
+
 	I915_WRITE(DEIER, de_ier);
 	POSTING_READ(DEIER);
 	I915_WRITE(SDEIER, sde_ier);
@@ -837,6 +873,9 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
 	if (de_iir & DE_PIPEB_VBLANK)
 		drm_handle_vblank(dev, 1);
 
+	if (de_iir & DE_POISON)
+		DRM_ERROR("Poison interrupt\n");
+
 	if (de_iir & DE_PLANEA_FLIP_DONE) {
 		intel_prepare_page_flip(dev, 0);
 		intel_finish_page_flip_plane(dev, 0);
@@ -1985,7 +2024,7 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 	/* enable kind of interrupts always enabled */
 	u32 display_mask = DE_MASTER_IRQ_CONTROL | DE_GSE | DE_PCH_EVENT |
 			   DE_PLANEA_FLIP_DONE | DE_PLANEB_FLIP_DONE |
-			   DE_AUX_CHANNEL_A;
+			   DE_AUX_CHANNEL_A | DE_POISON;
 	u32 render_irqs;
 
 	dev_priv->irq_mask = ~display_mask;
@@ -2035,12 +2074,14 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
 		DE_PLANEC_FLIP_DONE_IVB |
 		DE_PLANEB_FLIP_DONE_IVB |
 		DE_PLANEA_FLIP_DONE_IVB |
-		DE_AUX_CHANNEL_A_IVB;
+		DE_AUX_CHANNEL_A_IVB |
+		DE_ERR_INT_IVB;
 	u32 render_irqs;
 
 	dev_priv->irq_mask = ~display_mask;
 
 	/* should always can generate irq */
+	I915_WRITE(GEN7_ERR_INT, I915_READ(GEN7_ERR_INT));
 	I915_WRITE(DEIIR, I915_READ(DEIIR));
 	I915_WRITE(DEIMR, dev_priv->irq_mask);
 	I915_WRITE(DEIER,
@@ -2191,6 +2232,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
 	I915_WRITE(DEIMR, 0xffffffff);
 	I915_WRITE(DEIER, 0x0);
 	I915_WRITE(DEIIR, I915_READ(DEIIR));
+	if (IS_GEN7(dev))
+		I915_WRITE(GEN7_ERR_INT, I915_READ(GEN7_ERR_INT));
 
 	I915_WRITE(GTIMR, 0xffffffff);
 	I915_WRITE(GTIER, 0x0);
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 9cd59f7..f22e27d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -519,7 +519,8 @@
 
 #define ERROR_GEN6	0x040a0
 #define GEN7_ERR_INT	0x44040
-#define   ERR_INT_MMIO_UNCLAIMED (1<<13)
+#define   ERR_INT_POISON		(1<<31)
+#define   ERR_INT_MMIO_UNCLAIMED	(1<<13)
 
 #define FPGA_DBG		0x42300
 #define FPGA_DBG_RM_NOCLAIM	(1<<31)
@@ -3378,7 +3379,7 @@
 #define DE_PIPEA_FIFO_UNDERRUN  (1 << 0)
 
 /* More Ivybridge lolz */
-#define DE_ERR_DEBUG_IVB		(1<<30)
+#define DE_ERR_INT_IVB			(1<<30)
 #define DE_GSE_IVB			(1<<29)
 #define DE_PCH_EVENT_IVB		(1<<28)
 #define DE_DP_A_HOTPLUG_IVB		(1<<27)
