4 files changed, 36 insertions, 3 deletions

diff --git a/linux/drivers/media/video/uvc/uvc_driver.c b/linux/drivers/media/video/uvc/uvc_driver.c
index 1768389c4..13bd05576 100644
--- a/linux/drivers/media/video/uvc/uvc_driver.c
+++ b/linux/drivers/media/video/uvc/uvc_driver.c
@@ -1594,6 +1594,7 @@ static int uvc_probe(struct usb_interface *intf,
 	INIT_LIST_HEAD(&dev->entities);
 	INIT_LIST_HEAD(&dev->streaming);
 	kref_init(&dev->kref);
+	atomic_set(&dev->users, 0);
 
 	dev->udev = usb_get_dev(udev);
 	dev->intf = usb_get_intf(intf);
diff --git a/linux/drivers/media/video/uvc/uvc_status.c b/linux/drivers/media/video/uvc/uvc_status.c
index 1e1bda413..b05df63b4 100644
--- a/linux/drivers/media/video/uvc/uvc_status.c
+++ b/linux/drivers/media/video/uvc/uvc_status.c
@@ -206,7 +206,7 @@ int uvc_status_init(struct uvc_device *dev)
 		dev->status, UVC_MAX_STATUS_SIZE, uvc_status_complete,
 		dev, interval);
 
-	return usb_submit_urb(dev->int_urb, GFP_KERNEL);
+	return 0;
 }
 
 void uvc_status_cleanup(struct uvc_device *dev)
@@ -217,15 +217,30 @@ void uvc_status_cleanup(struct uvc_device *dev)
 	uvc_input_cleanup(dev);
 }
 
-int uvc_status_suspend(struct uvc_device *dev)
+int uvc_status_start(struct uvc_device *dev)
+{
+	if (dev->int_urb == NULL)
+		return 0;
+
+	return usb_submit_urb(dev->int_urb, GFP_KERNEL);
+}
+
+void uvc_status_stop(struct uvc_device *dev)
 {
 	usb_kill_urb(dev->int_urb);
+}
+
+int uvc_status_suspend(struct uvc_device *dev)
+{
+	if (atomic_read(&dev->users))
+		usb_kill_urb(dev->int_urb);
+
 	return 0;
 }
 
 int uvc_status_resume(struct uvc_device *dev)
 {
-	if (dev->int_urb == NULL)
+	if (dev->int_urb == NULL || atomic_read(&dev->users) == 0)
 		return 0;
 
 	return usb_submit_urb(dev->int_urb, GFP_NOIO);
diff --git a/linux/drivers/media/video/uvc/uvc_v4l2.c b/linux/drivers/media/video/uvc/uvc_v4l2.c
index bc13dbf05..160c01314 100644
--- a/linux/drivers/media/video/uvc/uvc_v4l2.c
+++ b/linux/drivers/media/video/uvc/uvc_v4l2.c
@@ -443,6 +443,17 @@ static int uvc_v4l2_open(struct file *file)
 		goto done;
 	}
 
+	if (atomic_inc_return(&video->dev->users) == 1) {
+		if ((ret = uvc_status_start(video->dev)) < 0) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 19)
+			usb_autopm_put_interface(video->dev->intf);
+#endif
+			atomic_dec(&video->dev->users);
+			kfree(handle);
+			goto done;
+		}
+	}
+
 	handle->device = video;
 	handle->state = UVC_HANDLE_PASSIVE;
 	file->private_data = handle;
@@ -477,6 +488,9 @@ static int uvc_v4l2_release(struct file *file)
 	kfree(handle);
 	file->private_data = NULL;
 
+	if (atomic_dec_return(&video->dev->users) == 0)
+		uvc_status_stop(video->dev);
+
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 19)
 	usb_autopm_put_interface(video->dev->intf);
 #endif
diff --git a/linux/drivers/media/video/uvc/uvcvideo.h b/linux/drivers/media/video/uvc/uvcvideo.h
index 53d5c9e0c..6b254fd39 100644
--- a/linux/drivers/media/video/uvc/uvcvideo.h
+++ b/linux/drivers/media/video/uvc/uvcvideo.h
@@ -635,6 +635,7 @@ struct uvc_device {
 	enum uvc_device_state state;
 	struct kref kref;
 	struct list_head list;
+	atomic_t users;
 
 	/* Video control interface */
 	__u16 uvc_version;
@@ -771,6 +772,8 @@ extern int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
 /* Status */
 extern int uvc_status_init(struct uvc_device *dev);
 extern void uvc_status_cleanup(struct uvc_device *dev);
+extern int uvc_status_start(struct uvc_device *dev);
+extern void uvc_status_stop(struct uvc_device *dev);
 extern int uvc_status_suspend(struct uvc_device *dev);
 extern int uvc_status_resume(struct uvc_device *dev);