i915: Don't run retire work handler while suspended

At leavevt and lastclose time, cancel any pending retire work handler
invocation, and keep the retire work handler from requeuing itself if it is
currently running.

This patch restructures i915_gem_idle to perform all of these tasks instead
of having both leavevt and lastclose call a sequence of functions.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -50,6 +50,9 @@ static int i915_gem_object_get_page_list(struct drm_gem_object *obj);
 static void i915_gem_object_free_page_list(struct drm_gem_object *obj);
 static int i915_gem_object_wait_rendering(struct drm_gem_object *obj);
 
+static void
+i915_gem_cleanup_ringbuffer(struct drm_device *dev);
+
 int
 i915_gem_init_ioctl(struct drm_device *dev, void *data,
 		    struct drm_file *file_priv)
@@ -582,7 +585,7 @@ i915_add_request(struct drm_device *dev, uint32_t flush_domains)
 	was_empty = list_empty(&dev_priv->mm.request_list);
 	list_add_tail(&request->list, &dev_priv->mm.request_list);
 
-	if (was_empty)
+	if (was_empty && !dev_priv->mm.suspended)
 		schedule_delayed_work(&dev_priv->mm.retire_work, HZ);
 	return seqno;
 }
@@ -731,7 +734,8 @@ i915_gem_retire_work_handler(struct work_struct *work)
 
 	mutex_lock(&dev->struct_mutex);
 	i915_gem_retire_requests(dev);
-	if (!list_empty(&dev_priv->mm.request_list))
+	if (!dev_priv->mm.suspended &&
+	    !list_empty(&dev_priv->mm.request_list))
 		schedule_delayed_work(&dev_priv->mm.retire_work, HZ);
 	mutex_unlock(&dev->struct_mutex);
 }
@@ -2227,14 +2231,24 @@ i915_gem_idle(struct drm_device *dev)
 	uint32_t seqno, cur_seqno, last_seqno;
 	int stuck, ret;
 
-	if (dev_priv->mm.suspended)
+	mutex_lock(&dev->struct_mutex);
+
+	if (dev_priv->mm.suspended || dev_priv->ring.ring_obj == NULL) {
+		mutex_unlock(&dev->struct_mutex);
 		return 0;
+	}
 
 	/* 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;
 
+	/* Cancel the retire work handler, wait for it to finish if running
+	 */
+	mutex_unlock(&dev->struct_mutex);
+	cancel_delayed_work_sync(&dev_priv->mm.retire_work);
+	mutex_lock(&dev->struct_mutex);
+
 	i915_kernel_lost_context(dev);
 
 	/* Flush the GPU along with all non-CPU write domains
@@ -2284,13 +2298,19 @@ i915_gem_idle(struct drm_device *dev)
 
 	/* Move all buffers out of the GTT. */
 	ret = i915_gem_evict_from_list(dev, &dev_priv->mm.inactive_list);
-	if (ret)
+	if (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));
 	BUG_ON(!list_empty(&dev_priv->mm.request_list));
+
+	i915_gem_cleanup_ringbuffer(dev);
+	mutex_unlock(&dev->struct_mutex);
+
 	return 0;
 }
 
@@ -2503,34 +2523,20 @@ i915_gem_leavevt_ioctl(struct drm_device *dev, void *data,
 {
 	int ret;
 
-	mutex_lock(&dev->struct_mutex);
 	ret = i915_gem_idle(dev);
-	if (ret == 0)
-		i915_gem_cleanup_ringbuffer(dev);
-	mutex_unlock(&dev->struct_mutex);
-
 	drm_irq_uninstall(dev);
 
-	return 0;
+	return ret;
 }
 
 void
 i915_gem_lastclose(struct drm_device *dev)
 {
 	int ret;
-	drm_i915_private_t *dev_priv = dev->dev_private;
-
-	mutex_lock(&dev->struct_mutex);
-
-	if (dev_priv->ring.ring_obj != NULL) {
-		ret = i915_gem_idle(dev);
-		if (ret)
-			DRM_ERROR("failed to idle hardware: %d\n", ret);
-
-		i915_gem_cleanup_ringbuffer(dev);
-	}
 
-	mutex_unlock(&dev->struct_mutex);
+	ret = i915_gem_idle(dev);
+	if (ret)
+		DRM_ERROR("failed to idle hardware: %d\n", ret);
 }
 
 void