Merge commit 'origin/drm-gem' into modesetting-gem

Use new GEM based ring buffer initialization.  Still need to init GEM & use it
for framebuffer allocation etc.

Conflicts:

	shared-core/i915_dma.c
	shared-core/i915_drv.h

8 files changed, 265 insertions, 73 deletions

diff --git a/linux-core/drmP.h b/linux-core/drmP.h
index c18159f8..ffe8b8ef 100644
--- a/linux-core/drmP.h
+++ b/linux-core/drmP.h
@@ -1453,6 +1453,9 @@ drm_gem_init (struct drm_device *dev);
 void
 drm_gem_object_free (struct kref *kref);
 
+struct drm_gem_object *
+drm_gem_object_alloc(struct drm_device *dev, size_t size);
+
 void
 drm_gem_object_handle_free (struct kref *kref);
     
diff --git a/linux-core/drm_gem.c b/linux-core/drm_gem.c
index b726e598..a8ecaf76 100644
--- a/linux-core/drm_gem.c
+++ b/linux-core/drm_gem.c
@@ -80,7 +80,7 @@ drm_gem_init(struct drm_device *dev)
 /**
  * Allocate a GEM object of the specified size with shmfs backing store
  */
-static struct drm_gem_object *
+struct drm_gem_object *
 drm_gem_object_alloc(struct drm_device *dev, size_t size)
 {
 	struct drm_gem_object *obj;
@@ -117,6 +117,7 @@ drm_gem_object_alloc(struct drm_device *dev, size_t size)
 	atomic_inc(&dev->object_count);
 	return obj;
 }
+EXPORT_SYMBOL(drm_gem_object_alloc);
 
 /**
  * Removes the mapping from handle to filp for this object.
diff --git a/linux-core/i915_gem.c b/linux-core/i915_gem.c
index b2870893..961831c6 100644
--- a/linux-core/i915_gem.c
+++ b/linux-core/i915_gem.c
@@ -702,14 +702,17 @@ i915_gem_object_get_page_list(struct drm_gem_object *obj)
 	BUG_ON(obj_priv->page_list != NULL);
 	obj_priv->page_list = drm_calloc(page_count, sizeof(struct page *),
 					 DRM_MEM_DRIVER);
-	if (obj_priv->page_list == NULL)
+	if (obj_priv->page_list == NULL) {
+		DRM_ERROR("Faled to allocate page list\n");
 		return -ENOMEM;
+	}
 
 	for (i = 0; i < page_count; i++) {
 		obj_priv->page_list[i] =
 		    find_or_create_page(obj->filp->f_mapping, i, GFP_HIGHUSER);
 
 		if (obj_priv->page_list[i] == NULL) {
+			DRM_ERROR("Failed to find_or_create_page()\n");
 			i915_gem_object_free_page_list(obj);
 			return -ENOMEM;
 		}
@@ -758,14 +761,17 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
 		DRM_INFO("%s: GTT full, evicting something\n", __func__);
 #endif
 		if (list_empty(&dev_priv->mm.inactive_list) &&
+		    list_empty(&dev_priv->mm.flushing_list) &&
 		    list_empty(&dev_priv->mm.active_list)) {
 			DRM_ERROR("GTT full, but LRU list empty\n");
 			return -ENOMEM;
 		}
 
 		ret = i915_gem_evict_something(dev);
-		if (ret != 0)
+		if (ret != 0) {
+			DRM_ERROR("Failed to evict a buffer\n");
 			return ret;
+		}
 		goto search_free;
 	}
 
@@ -1383,6 +1389,7 @@ int
 i915_gem_execbuffer(struct drm_device *dev, void *data,
 		    struct drm_file *file_priv)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_execbuffer *args = data;
 	struct drm_i915_gem_exec_object *exec_list = NULL;
 	struct drm_gem_object **object_list = NULL;
@@ -1423,6 +1430,12 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
 
 	mutex_lock(&dev->struct_mutex);
 
+	if (dev_priv->mm.suspended) {
+		DRM_ERROR("Execbuf while VT-switched.\n");
+		mutex_unlock(&dev->struct_mutex);
+		return -EBUSY;
+	}
+
 	/* Zero the gloabl flush/invalidate flags. These
 	 * will be modified as each object is bound to the
 	 * gtt
@@ -1560,6 +1573,37 @@ pre_mutex_err:
 }
 
 int
+i915_gem_object_pin(struct drm_gem_object *obj, uint32_t alignment)
+{
+	struct drm_device *dev = obj->dev;
+	struct drm_i915_gem_object *obj_priv = obj->driver_private;
+	int ret;
+
+	if (obj_priv->gtt_space == NULL) {
+		ret = i915_gem_object_bind_to_gtt(obj, alignment);
+		if (ret != 0) {
+			DRM_ERROR("Failure to bind in "
+				  "i915_gem_pin_ioctl(): %d\n",
+				  ret);
+			drm_gem_object_unreference(obj);
+			mutex_unlock(&dev->struct_mutex);
+			return ret;
+		}
+	}
+
+	obj_priv->pin_count++;
+	return 0;
+}
+
+void
+i915_gem_object_unpin(struct drm_gem_object *obj)
+{
+	struct drm_i915_gem_object *obj_priv = obj->driver_private;
+
+	obj_priv->pin_count--;
+}
+
+int
 i915_gem_pin_ioctl(struct drm_device *dev, void *data,
 		   struct drm_file *file_priv)
 {
@@ -1578,22 +1622,15 @@ i915_gem_pin_ioctl(struct drm_device *dev, void *data,
 		mutex_unlock(&dev->struct_mutex);
 		return -EINVAL;
 	}
-
 	obj_priv = obj->driver_private;
-	if (obj_priv->gtt_space == NULL) {
-		ret = i915_gem_object_bind_to_gtt(obj,
-						  (unsigned) args->alignment);
-		if (ret != 0) {
-			DRM_ERROR("Failure to bind in "
-				  "i915_gem_pin_ioctl(): %d\n",
-				  ret);
-			drm_gem_object_unreference(obj);
-			mutex_unlock(&dev->struct_mutex);
-			return ret;
-		}
+
+	ret = i915_gem_object_pin(obj, args->alignment);
+	if (ret != 0) {
+		drm_gem_object_unreference(obj);
+		mutex_unlock(&dev->struct_mutex);
+		return ret;
 	}
 
-	obj_priv->pin_count++;
 	args->offset = obj_priv->gtt_offset;
 	drm_gem_object_unreference(obj);
 	mutex_unlock(&dev->struct_mutex);
@@ -1607,7 +1644,6 @@ i915_gem_unpin_ioctl(struct drm_device *dev, void *data,
 {
 	struct drm_i915_gem_pin *args = data;
 	struct drm_gem_object *obj;
-	struct drm_i915_gem_object *obj_priv;
 
 	mutex_lock(&dev->struct_mutex);
 
@@ -1620,8 +1656,8 @@ i915_gem_unpin_ioctl(struct drm_device *dev, void *data,
 		return -EINVAL;
 	}
 
-	obj_priv = obj->driver_private;
-	obj_priv->pin_count--;
+	i915_gem_object_unpin(obj);
+
 	drm_gem_object_unreference(obj);
 	mutex_unlock(&dev->struct_mutex);
 	return 0;
@@ -1757,3 +1793,173 @@ i915_gem_lastclose(struct drm_device *dev)
 
 	mutex_unlock(&dev->struct_mutex);
 }
+
+int
+i915_gem_init_ringbuffer(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_gem_object *obj;
+	struct drm_i915_gem_object *obj_priv;
+	int ret;
+
+	obj = drm_gem_object_alloc(dev, 128 * 1024);
+	if (obj == NULL) {
+		DRM_ERROR("Failed to allocate ringbuffer\n");
+		return -ENOMEM;
+	}
+	obj_priv = obj->driver_private;
+
+	ret = i915_gem_object_pin(obj, 4096);
+	if (ret != 0)
+		return ret;
+
+	/* Set up the kernel mapping for the ring. */
+	dev_priv->ring.Size = obj->size;
+	dev_priv->ring.tail_mask = obj->size - 1;
+
+	dev_priv->ring.map.offset = dev->agp->base + obj_priv->gtt_offset;
+	dev_priv->ring.map.size = obj->size;
+	dev_priv->ring.map.type = 0;
+	dev_priv->ring.map.flags = 0;
+	dev_priv->ring.map.mtrr = 0;
+
+	drm_core_ioremap(&dev_priv->ring.map, dev);
+	if (dev_priv->ring.map.handle == NULL) {
+		DRM_ERROR("Failed to map ringbuffer.\n");
+		memset(&dev_priv->ring, 0, sizeof(dev_priv->ring));
+		drm_gem_object_unreference(obj);
+		return -EINVAL;
+	}
+	dev_priv->ring.ring_obj = obj;
+	dev_priv->ring.virtual_start = dev_priv->ring.map.handle;
+
+	/* Stop the ring if it's running. */
+	I915_WRITE(LP_RING + RING_LEN, 0);
+	I915_WRITE(LP_RING + RING_HEAD, 0);
+	I915_WRITE(LP_RING + RING_TAIL, 0);
+	I915_WRITE(LP_RING + RING_START, 0);
+
+	/* Initialize the ring. */
+	I915_WRITE(LP_RING + RING_START, obj_priv->gtt_offset);
+	I915_WRITE(LP_RING + RING_LEN,
+		   ((obj->size - 4096) & RING_NR_PAGES) |
+		   RING_NO_REPORT |
+		   RING_VALID);
+
+	/* Update our cache of the ring state */
+	i915_kernel_lost_context(dev);
+
+	return 0;
+}
+
+static void
+i915_gem_cleanup_ringbuffer(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (dev_priv->ring.ring_obj == NULL)
+		return;
+
+	drm_core_ioremapfree(&dev_priv->ring.map, dev);
+
+	i915_gem_object_unpin(dev_priv->ring.ring_obj);
+	drm_gem_object_unreference(dev_priv->ring.ring_obj);
+
+	memset(&dev_priv->ring, 0, sizeof(dev_priv->ring));
+}
+
+int
+i915_gem_entervt_ioctl(struct drm_device *dev, void *data,
+		       struct drm_file *file_priv)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret;
+
+	ret = i915_gem_init_ringbuffer(dev);
+	if (ret != 0)
+		return ret;
+
+	mutex_lock(&dev->struct_mutex);
+	dev_priv->mm.suspended = 0;
+	mutex_unlock(&dev->struct_mutex);
+	return 0;
+}
+
+/** Unbinds all objects that are on the given buffer list. */
+static int
+i915_gem_evict_from_list(struct drm_device *dev, struct list_head *head)
+{
+	struct drm_gem_object *obj;
+	struct drm_i915_gem_object *obj_priv;
+	int ret;
+
+	while (!list_empty(head)) {
+		obj_priv = list_first_entry(head,
+					    struct drm_i915_gem_object,
+					    list);
+		obj = obj_priv->obj;
+
+		if (obj_priv->pin_count != 0) {
+			DRM_ERROR("Pinned object in unbind list\n");
+			mutex_unlock(&dev->struct_mutex);
+			return -EINVAL;
+		}
+
+		ret = i915_gem_object_unbind(obj);
+		if (ret != 0) {
+			DRM_ERROR("Error unbinding object in LeaveVT: %d\n",
+				  ret);
+			mutex_unlock(&dev->struct_mutex);
+			return ret;
+		}
+	}
+
+
+	return 0;
+}
+
+int
+i915_gem_leavevt_ioctl(struct drm_device *dev, void *data,
+		       struct drm_file *file_priv)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	mutex_lock(&dev->struct_mutex);
+	/* Hack!  Don't let anybody do execbuf while we don't control the chip.
+	 * We need to replace this with a semaphore, or something.
+	 */
+	dev_priv->mm.suspended = 1;
+
+	/* Move all buffers out of the GTT. */
+	i915_gem_evict_from_list(dev, &dev_priv->mm.active_list);
+	i915_gem_evict_from_list(dev, &dev_priv->mm.flushing_list);
+	i915_gem_evict_from_list(dev, &dev_priv->mm.inactive_list);
+
+	/* Make sure the harware's idle. */
+	while (!list_empty(&dev_priv->mm.request_list)) {
+		struct drm_i915_gem_request *request;
+		int ret;
+
+		request = list_first_entry(&dev_priv->mm.request_list,
+					   struct drm_i915_gem_request,
+					   list);
+
+		ret = i915_wait_request(dev, request->seqno);
+		if (ret != 0) {
+			DRM_ERROR("Error waiting for idle at LeaveVT: %d\n",
+				  ret);
+			mutex_unlock(&dev->struct_mutex);
+			return ret;
+		}
+	}
+
+	BUG_ON(!list_empty(&dev_priv->mm.active_list));
+	BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
+	BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
+
+	i915_gem_cleanup_ringbuffer(dev);
+
+	mutex_unlock(&dev->struct_mutex);
+
+	return 0;
+}
diff --git a/shared-core/i915_dma.c b/shared-core/i915_dma.c
index 86881ab8..1e51e702 100644
--- a/shared-core/i915_dma.c
+++ b/shared-core/i915_dma.c
@@ -232,20 +232,16 @@ static int i915_initialize(struct drm_device * dev,
 	}
 #endif
 
-	if (!dev_priv->ring.Size) {
-		dev_priv->ring.Start = init->ring_start;
-		dev_priv->ring.End = init->ring_end;
+	if (init->ring_size != 0) {
 		dev_priv->ring.Size = init->ring_size;
 		dev_priv->ring.tail_mask = dev_priv->ring.Size - 1;
-		
 		dev_priv->ring.map.offset = init->ring_start;
 		dev_priv->ring.map.size = init->ring_size;
 		dev_priv->ring.map.type = 0;
 		dev_priv->ring.map.flags = 0;
 		dev_priv->ring.map.mtrr = 0;
-		
 		drm_core_ioremap(&dev_priv->ring.map, dev);
-		
+
 		if (dev_priv->ring.map.handle == NULL) {
 			i915_dma_cleanup(dev);
 			DRM_ERROR("can not ioremap virtual address for"
@@ -255,7 +251,6 @@ static int i915_initialize(struct drm_device * dev,
 		dev_priv->ring.virtual_start = dev_priv->ring.map.handle;
 	}
 
-
 	dev_priv->cpp = init->cpp;
 	master_priv->sarea_priv->pf_current_page = 0;
 
@@ -1091,6 +1086,8 @@ struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_I915_GEM_UNPIN, i915_gem_unpin_ioctl, DRM_AUTH|DRM_ROOT_ONLY),
 	DRM_IOCTL_DEF(DRM_I915_GEM_BUSY, i915_gem_busy_ioctl, DRM_AUTH),
 	DRM_IOCTL_DEF(DRM_I915_GEM_THROTTLE, i915_gem_throttle_ioctl, DRM_AUTH),
+	DRM_IOCTL_DEF(DRM_I915_GEM_ENTERVT, i915_gem_entervt_ioctl, DRM_AUTH),
+	DRM_IOCTL_DEF(DRM_I915_GEM_LEAVEVT, i915_gem_leavevt_ioctl, DRM_AUTH),
 };
 
 int i915_max_ioctl = DRM_ARRAY_SIZE(i915_ioctls);
diff --git a/shared-core/i915_drm.h b/shared-core/i915_drm.h
index bb551d84..445bb279 100644
--- a/shared-core/i915_drm.h
+++ b/shared-core/i915_drm.h
@@ -182,6 +182,8 @@ typedef struct drm_i915_sarea {
 #define DRM_I915_GEM_UNPIN	0x16
 #define DRM_I915_GEM_BUSY	0x17
 #define DRM_I915_GEM_THROTTLE	0x18
+#define DRM_I915_GEM_ENTERVT	0x19
+#define DRM_I915_GEM_LEAVEVT	0x20
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
 #define DRM_IOCTL_I915_FLUSH		DRM_IO ( DRM_COMMAND_BASE + DRM_I915_FLUSH)
@@ -207,6 +209,8 @@ typedef struct drm_i915_sarea {
 #define DRM_IOCTL_I915_GEM_UNPIN	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_GEM_UNPIN, struct drm_i915_gem_unpin)
 #define DRM_IOCTL_I915_GEM_BUSY		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_BUSY, struct drm_i915_gem_busy)
 #define DRM_IOCTL_I915_GEM_THROTTLE	DRM_IO ( DRM_COMMAND_BASE + DRM_I915_GEM_THROTTLE)
+#define DRM_IOCTL_I915_GEM_ENTERVT	DRM_IO(DRM_COMMAND_BASE + DRM_I915_GEM_ENTERVT)
+#define DRM_IOCTL_I915_GEM_LEAVEVT	DRM_IO(DRM_COMMAND_BASE + DRM_I915_GEM_LEAVEVT)
 
 /* Asynchronous page flipping:
  */
diff --git a/shared-core/i915_drv.h b/shared-core/i915_drv.h
index eab51e39..cfb064ff 100644
--- a/shared-core/i915_drv.h
+++ b/shared-core/i915_drv.h
@@ -81,14 +81,13 @@ struct drm_i915_validate_buffer;
 
 struct drm_i915_ring_buffer {
 	int tail_mask;
-	unsigned long Start;
-	unsigned long End;
 	unsigned long Size;
 	u8 *virtual_start;
 	int head;
 	int tail;
 	int space;
 	drm_local_map_t map;
+	struct drm_gem_object *ring_obj;
 };
 
 struct mem_block {
@@ -236,6 +235,16 @@ struct drm_i915_private {
 		struct work_struct retire_task;
 		
 		uint32_t next_gem_seqno;
+
+                /**
+                 * Flag if the X Server, and thus DRM, is not currently in
+                 * control of the device.
+                 *
+                 * This is set between LeaveVT and EnterVT.  It needs to be
+                 * replaced with a semaphore.  It also needs to be
+                 * transitioned away from for kernel modesetting.
+                 */
+                int suspended;
 	} mm;
 
 	struct work_struct user_interrupt_task;
@@ -502,8 +511,14 @@ int i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
 int i915_gem_throttle_ioctl(struct drm_device *dev, void *data,
 			    struct drm_file *file_priv);
+int i915_gem_entervt_ioctl(struct drm_device *dev, void *data,
+			   struct drm_file *file_priv);
+int i915_gem_leavevt_ioctl(struct drm_device *dev, void *data,
+			   struct drm_file *file_priv);
 int i915_gem_init_object(struct drm_gem_object *obj);
 void i915_gem_free_object(struct drm_gem_object *obj);
+int i915_gem_object_pin(struct drm_gem_object *obj, uint32_t alignment);
+void i915_gem_object_unpin(struct drm_gem_object *obj);
 int i915_gem_set_domain(struct drm_gem_object *obj,
 			struct drm_file *file_priv,
 			uint32_t read_domains,
@@ -514,6 +529,7 @@ void i915_gem_lastclose(struct drm_device *dev);
 void i915_gem_retire_requests(struct drm_device *dev);
 void i915_gem_retire_timeout(unsigned long data);
 void i915_gem_retire_handler(struct work_struct *work);
+int i915_gem_init_ringbuffer(struct drm_device *dev);
 #endif
 
 extern unsigned int i915_fbpercrtc;
diff --git a/shared-core/i915_init.c b/shared-core/i915_init.c
index e13d12fc..ba02f485 100644
--- a/shared-core/i915_init.c
+++ b/shared-core/i915_init.c
@@ -109,47 +109,9 @@ int i915_load_modeset_init(struct drm_device *dev)
 	i915_probe_agp(dev->pdev, &agp_size, &prealloc_size);
 	printk("setting up %ld bytes of VRAM space\n", prealloc_size);
 	printk("setting up %ld bytes of TT space\n", (agp_size - prealloc_size));
-
-	drm_bo_init_mm(dev, DRM_BO_MEM_VRAM, 0, prealloc_size >> PAGE_SHIFT, 1);
-	drm_bo_init_mm(dev, DRM_BO_MEM_TT, prealloc_size >> PAGE_SHIFT,
-		       (agp_size - prealloc_size) >> PAGE_SHIFT, 1);
-	I915_WRITE(PRB0_CTL, 0);
-	I915_WRITE(PRB0_HEAD, 0);
-	I915_WRITE(PRB0_TAIL, 0);
-
-	size = PRIMARY_RINGBUFFER_SIZE;
-	ret = drm_buffer_object_create(dev, size, drm_bo_type_kernel,
-			DRM_BO_FLAG_READ | DRM_BO_FLAG_WRITE |
-			DRM_BO_FLAG_MEM_VRAM |
-			DRM_BO_FLAG_NO_EVICT,
-			DRM_BO_HINT_DONT_FENCE, 0x1, 0,
-			&dev_priv->ring_buffer);
-	if (ret < 0) {
-		DRM_ERROR("Unable to allocate or pin ring buffer\n");
-		goto clean_mm;
-	}
-
-	/* remap the buffer object properly */
-	dev_priv->ring.Start = dev_priv->ring_buffer->offset;
-	dev_priv->ring.End = dev_priv->ring.Start + size;
-	dev_priv->ring.Size = size;
-	dev_priv->ring.tail_mask = dev_priv->ring.Size - 1;
-
-	/* FIXME: need wrapper with PCI mem checks */
-	ret = drm_mem_reg_ioremap(dev, &dev_priv->ring_buffer->mem,
-				  (void **) &dev_priv->ring.virtual_start);
-	if (ret) {
-		DRM_ERROR("error mapping ring buffer: %d\n", ret);
-		goto destroy_ringbuffer;
-	}
-
-	DRM_DEBUG("ring start %08lX, %p, %08lX\n", dev_priv->ring.Start,
-			dev_priv->ring.virtual_start, dev_priv->ring.Size);
-
-	memset((void *)(dev_priv->ring.virtual_start), 0, dev_priv->ring.Size);
-	I915_WRITE(PRB0_START, dev_priv->ring.Start);
-	I915_WRITE(PRB0_CTL, ((dev_priv->ring.Size - 4096) & RING_NR_PAGES) |
-		   (RING_NO_REPORT | RING_VALID));
+	ret = i915_gem_init_ringbuffer(dev);
+	if (ret)
+		goto out;
 
 	/* Allow hardware batchbuffers unless told otherwise.
 	 */
@@ -262,9 +224,7 @@ destroy_ringbuffer:
 				    dev_priv->ring.virtual_start);
 	if (dev_priv->ring_buffer)
 		drm_bo_usage_deref_unlocked(&dev_priv->ring_buffer);
-clean_mm:
-	drm_bo_clean_mm(dev, DRM_BO_MEM_VRAM, 1);
-	drm_bo_clean_mm(dev, DRM_BO_MEM_TT, 1);
+out:
 	return ret;
 }
 
diff --git a/shared-core/i915_irq.c b/shared-core/i915_irq.c
index d36a3691..bd11d37a 100644
--- a/shared-core/i915_irq.c
+++ b/shared-core/i915_irq.c
@@ -670,7 +670,7 @@ void i915_user_irq_off(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = (struct drm_i915_private *) dev->dev_private;
 
 	DRM_SPINLOCK(&dev_priv->user_irq_lock);
-	BUG_ON(dev_priv->user_irq_refcount <= 0);
+	BUG_ON(dev_priv->irq_enabled && dev_priv->user_irq_refcount <= 0);
 	if (dev_priv->irq_enabled && (--dev_priv->user_irq_refcount == 0)) {
 		dev_priv->irq_mask_reg |= I915_USER_INTERRUPT;
 		if (IS_I9XX(dev) && !IS_I915G(dev) && !IS_I915GM(dev))
@@ -689,6 +689,11 @@ int i915_wait_irq(struct drm_device * dev, int irq_nr)
 	struct drm_i915_master_private *master_priv;
 	int ret = 0;
 
+	if (!dev_priv) {
+		DRM_ERROR("called with no initialization\n");
+		return -EINVAL;
+	}
+
 	DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
 		  READ_BREADCRUMB(dev_priv));