diff --git a/shared-core/i915_dma.c b/shared-core/i915_dma.c
index d64c8854..1e17d9ed 100644
--- a/shared-core/i915_dma.c
+++ b/shared-core/i915_dma.c
@@ -109,6 +109,11 @@ static void i915_bmp_free(drm_device_t *dev)
 		dev_priv->bmp = NULL;
 	}
 
+	I915_WRITE(BMP_BUFFER, 0);
+
+	dev_priv->irq_enable_reg &= ~HWB_OOM_FLAG;
+	I915_WRITE(I915REG_INT_ENABLE_R, dev_priv->irq_enable_reg);
+
 	DRM_INFO("BMP freed\n");
 }
 
@@ -800,6 +805,9 @@ static int i915_bmp_alloc(drm_device_t *dev)
 	I915_WRITE(BMP_PUT, (i / 8) << BMP_OFFSET_SHIFT);
 	I915_WRITE(BMP_GET, 0 << BMP_OFFSET_SHIFT);
 
+	dev_priv->irq_enable_reg |= HWB_OOM_FLAG;
+	I915_WRITE(I915REG_INT_ENABLE_R, dev_priv->irq_enable_reg);
+
 	I915_WRITE(BMP_BUFFER, dev_priv->bmp->busaddr | BMP_PAGE_SIZE_4K |
 		   ((BMP_SIZE / PAGE_SIZE - 1) << BMP_BUFFER_SIZE_SHIFT) |
 		   BMP_ENABLE);
@@ -1586,15 +1594,21 @@ static int i915_hwz_init(drm_device_t *dev, struct drm_i915_hwz_init *init)
 static int i915_hwz(DRM_IOCTL_ARGS)
 {
 	DRM_DEVICE;
+	drm_i915_private_t *dev_priv = dev->dev_private;
 	drm_file_t *filp_priv;
 	struct drm_i915_driver_file_fields *filp_i915priv;
 	drm_i915_hwz_t hwz;
 
-	if (!dev->dev_private) {
+	if (!dev_priv) {
 		DRM_ERROR("called with no initialization\n");
 		return DRM_ERR(EINVAL);
 	}
 
+	if (dev_priv->hwb_oom) {
+		DRM_ERROR("HWB out of memory\n");
+		return DRM_ERR(ENOMEM);
+	}
+
 	DRM_COPY_FROM_USER_IOCTL(hwz, (drm_i915_hwz_t __user *) data,
 				 sizeof(hwz));
 
diff --git a/shared-core/i915_drv.h b/shared-core/i915_drv.h
index f7d0b3ca..dddd75a7 100644
--- a/shared-core/i915_drv.h
+++ b/shared-core/i915_drv.h
@@ -135,6 +135,8 @@ typedef struct drm_i915_private {
 	drm_i915_vbl_swap_t vbl_swaps;
 	unsigned int swaps_pending;
 
+	int hwb_oom;
+
 	drm_dma_handle_t *bmp, **bmp_pool;
 
 	unsigned long priv1_addr;
@@ -298,6 +300,11 @@ extern int i915_wait_ring(drm_i915_private_t *dev_priv, drm_i915_ring_buffer_t
 #define BB1_UNPROTECTED       (0<<0)
 #define BB2_END_ADDR_MASK     (~0x7)
 
+#define USER_INT_FLAG    (1<<1)
+#define VSYNC_PIPEB_FLAG (1<<5)
+#define VSYNC_PIPEA_FLAG (1<<7)
+#define HWB_OOM_FLAG     (1<<13)
+
 #define I915REG_HWSTAM		0x02098
 #define I915REG_INT_IDENTITY_R	0x020a4
 #define I915REG_INT_MASK_R 	0x020a8
diff --git a/shared-core/i915_irq.c b/shared-core/i915_irq.c
index cae7eba3..c00d82c6 100644
--- a/shared-core/i915_irq.c
+++ b/shared-core/i915_irq.c
@@ -31,10 +31,6 @@
 #include "i915_drm.h"
 #include "i915_drv.h"
 
-#define USER_INT_FLAG (1<<1)
-#define VSYNC_PIPEB_FLAG (1<<5)
-#define VSYNC_PIPEA_FLAG (1<<7)
-
 #define MAX_NOPID ((u32)~0)
 
 /**
@@ -285,7 +281,7 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 	pipeb_stats = I915_READ(I915REG_PIPEBSTAT);
 		
 	temp = I915_READ(I915REG_INT_IDENTITY_R);
-	temp &= (dev_priv->irq_enable_reg | USER_INT_FLAG);
+	temp &= (dev_priv->irq_enable_reg | USER_INT_FLAG | HWB_OOM_FLAG);
 
 #if 0
 	DRM_DEBUG("%s flag=%08x\n", __FUNCTION__, temp);
@@ -335,6 +331,11 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 			I915_VBLANK_CLEAR);
 	}
 
+	if ((temp & HWB_OOM_FLAG) && !dev_priv->hwb_oom) {
+		DRM_ERROR("HWB out of memory\n");
+		dev_priv->hwb_oom = TRUE;
+	}
+
 	return IRQ_HANDLED;
 }