diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 01511e5..2f09c7e 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -2527,9 +2527,13 @@ static int dvb_frontend_open(struct inode *inode, struct file *file)
 		fepriv->voltage = -1;
 
 #ifdef CONFIG_MEDIA_CONTROLLER_DVB
-		if (fe->dvb->mdev && fe->dvb->mdev->enable_source) {
-			ret = fe->dvb->mdev->enable_source(dvbdev->entity,
+		if (fe->dvb->mdev) {
+			mutex_lock(&fe->dvb->mdev->graph_mutex);
+			if (fe->dvb->mdev->enable_source)
+				ret = fe->dvb->mdev->enable_source(
+							   dvbdev->entity,
 							   &fepriv->pipe);
+			mutex_unlock(&fe->dvb->mdev->graph_mutex);
 			if (ret) {
 				dev_err(fe->dvb->device,
 					"Tuner is busy. Error %d\n", ret);
@@ -2553,8 +2557,12 @@ static int dvb_frontend_open(struct inode *inode, struct file *file)
 
 err3:
 #ifdef CONFIG_MEDIA_CONTROLLER_DVB
-	if (fe->dvb->mdev && fe->dvb->mdev->disable_source)
-		fe->dvb->mdev->disable_source(dvbdev->entity);
+	if (fe->dvb->mdev) {
+		mutex_lock(&fe->dvb->mdev->graph_mutex);
+		if (fe->dvb->mdev->disable_source)
+			fe->dvb->mdev->disable_source(dvbdev->entity);
+		mutex_unlock(&fe->dvb->mdev->graph_mutex);
+	}
 err2:
 #endif
 	dvb_generic_release(inode, file);
@@ -2586,8 +2594,12 @@ static int dvb_frontend_release(struct inode *inode, struct file *file)
 	if (dvbdev->users == -1) {
 		wake_up(&fepriv->wait_queue);
 #ifdef CONFIG_MEDIA_CONTROLLER_DVB
-		if (fe->dvb->mdev && fe->dvb->mdev->disable_source)
-			fe->dvb->mdev->disable_source(dvbdev->entity);
+		if (fe->dvb->mdev) {
+			mutex_lock(&fe->dvb->mdev->graph_mutex);
+			if (fe->dvb->mdev->disable_source)
+				fe->dvb->mdev->disable_source(dvbdev->entity);
+			mutex_unlock(&fe->dvb->mdev->graph_mutex);
+		}
 #endif
 		if (fe->exit != DVB_FE_NO_EXIT)
 			wake_up(&dvbdev->wait_queue);
diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
index bf53553..bfd6482 100644
--- a/drivers/media/usb/au0828/au0828-core.c
+++ b/drivers/media/usb/au0828/au0828-core.c
@@ -153,9 +153,11 @@ static void au0828_unregister_media_device(struct au0828_dev *dev)
 	}
 
 	/* clear enable_source, disable_source */
+	mutex_lock(&mdev->graph_mutex);
 	dev->media_dev->source_priv = NULL;
 	dev->media_dev->enable_source = NULL;
 	dev->media_dev->disable_source = NULL;
+	mutex_unlock(&mdev->graph_mutex);
 
 	media_device_unregister(dev->media_dev);
 	media_device_cleanup(dev->media_dev);
@@ -278,6 +280,7 @@ static void au0828_media_graph_notify(struct media_entity *new,
 	}
 }
 
+/* Callers should hold graph_mutex */
 static int au0828_enable_source(struct media_entity *entity,
 				struct media_pipeline *pipe)
 {
@@ -291,8 +294,6 @@ static int au0828_enable_source(struct media_entity *entity,
 	if (!mdev)
 		return -ENODEV;
 
-	mutex_lock(&mdev->graph_mutex);
-
 	dev = mdev->source_priv;
 
 	/*
@@ -419,12 +420,12 @@ static int au0828_enable_source(struct media_entity *entity,
 		 dev->active_source->name, dev->active_sink->name,
 		 dev->active_link_owner->name, ret);
 end:
-	mutex_unlock(&mdev->graph_mutex);
 	pr_debug("au0828_enable_source() end %s %d %d\n",
 		 entity->name, entity->function, ret);
 	return ret;
 }
 
+/* Callers should hold graph_mutex */
 static void au0828_disable_source(struct media_entity *entity)
 {
 	int ret = 0;
@@ -434,13 +435,10 @@ static void au0828_disable_source(struct media_entity *entity)
 	if (!mdev)
 		return;
 
-	mutex_lock(&mdev->graph_mutex);
 	dev = mdev->source_priv;
 
-	if (!dev->active_link) {
-		ret = -ENODEV;
-		goto end;
-	}
+	if (!dev->active_link)
+		return;
 
 	/* link is active - stop pipeline from source (tuner) */
 	if (dev->active_link->sink->entity == dev->active_sink &&
@@ -450,7 +448,7 @@ static void au0828_disable_source(struct media_entity *entity)
 		 * has active pipeline
 		*/
 		if (dev->active_link_owner != entity)
-			goto end;
+			return;
 		__media_entity_pipeline_stop(entity);
 		ret = __media_entity_setup_link(dev->active_link, 0);
 		if (ret)
@@ -465,9 +463,6 @@ static void au0828_disable_source(struct media_entity *entity)
 		dev->active_source = NULL;
 		dev->active_sink = NULL;
 	}
-
-end:
-	mutex_unlock(&mdev->graph_mutex);
 }
 #endif
 
@@ -549,9 +544,11 @@ static int au0828_media_device_register(struct au0828_dev *dev,
 		return ret;
 	}
 	/* set enable_source */
+	mutex_lock(&dev->media_dev->graph_mutex);
 	dev->media_dev->source_priv = (void *) dev;
 	dev->media_dev->enable_source = au0828_enable_source;
 	dev->media_dev->disable_source = au0828_disable_source;
+	mutex_unlock(&dev->media_dev->graph_mutex);
 #endif
 	return 0;
 }
diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
index 8bef433..b169d24 100644
--- a/drivers/media/v4l2-core/v4l2-mc.c
+++ b/drivers/media/v4l2-core/v4l2-mc.c
@@ -198,14 +198,20 @@ EXPORT_SYMBOL_GPL(v4l2_mc_create_media_graph);
 int v4l_enable_media_source(struct video_device *vdev)
 {
 	struct media_device *mdev = vdev->entity.graph_obj.mdev;
-	int ret;
+	int ret = 0, err;
 
-	if (!mdev || !mdev->enable_source)
+	if (!mdev)
 		return 0;
-	ret = mdev->enable_source(&vdev->entity, &vdev->pipe);
-	if (ret)
-		return -EBUSY;
-	return 0;
+
+	mutex_lock(&mdev->graph_mutex);
+	if (!mdev->enable_source)
+		goto end;
+	err = mdev->enable_source(&vdev->entity, &vdev->pipe);
+	if (err)
+		ret = -EBUSY;
+end:
+	mutex_unlock(&mdev->graph_mutex);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(v4l_enable_media_source);
 
@@ -213,8 +219,12 @@ void v4l_disable_media_source(struct video_device *vdev)
 {
 	struct media_device *mdev = vdev->entity.graph_obj.mdev;
 
-	if (mdev && mdev->disable_source)
-		mdev->disable_source(&vdev->entity);
+	if (mdev) {
+		mutex_lock(&mdev->graph_mutex);
+		if (mdev->disable_source)
+			mdev->disable_source(&vdev->entity);
+		mutex_unlock(&mdev->graph_mutex);
+	}
 }
 EXPORT_SYMBOL_GPL(v4l_disable_media_source);
 
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 633f2e3..1189ac8 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -123,6 +123,8 @@ struct media_device_ops {
  *    bridge driver finds the media_device during probe.
  *    Bridge driver sets source_priv with information
  *    necessary to run @enable_source and @disable_source handlers.
+ *    Callers should hold graph_mutex to access and call @enable_source
+ *    and @disable_source handlers.
  */
 struct media_device {
 	/* dev->driver_data points to this struct. */
