@@ -479,6 +479,7 @@ static int uvc_v4l2_open(struct file *file)
{
struct uvc_streaming *stream;
struct uvc_fh *handle;
+ unsigned long timeout;
int ret = 0;
uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_open\n");
@@ -499,7 +500,14 @@ static int uvc_v4l2_open(struct file *file)
}
if (atomic_inc_return(&stream->dev->users) == 1) {
- ret = uvc_status_start(stream->dev);
+ timeout = jiffies + msecs_to_jiffies(UVC_STATUS_START_TIMEOUT);
+ /* -EPERM means stop in progress, wait for completion */
+ do {
+ ret = uvc_status_start(stream->dev);
+ if (ret == -EPERM)
+ usleep_range(5000, 6000);
+ } while (ret == -EPERM && time_before(jiffies, timeout));
+
if (ret < 0) {
atomic_dec(&stream->dev->users);
usb_autopm_put_interface(stream->dev->intf);
@@ -122,6 +122,7 @@
#define UVC_CTRL_CONTROL_TIMEOUT 300
#define UVC_CTRL_STREAMING_TIMEOUT 5000
+#define UVC_STATUS_START_TIMEOUT 100
/* Maximum allowed number of control mappings per device */
#define UVC_MAX_CONTROL_MAPPINGS 1024
While usb_kill_urb is in progress, calls to usb_submit_urb will fail with -EPERM (documented in Documentation/usb/URB.txt). The UVC driver does not correctly handle this case -- there is no synchronization between uvc_v4l2_open / uvc_status_start and uvc_v4l2_release / uvc_status_stop. This patch adds a retry / timeout when uvc_status_open / usb_submit_urb returns -EPERM. This usually means that usb_kill_urb is in progress, and we just need to wait a while. Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org> --- drivers/media/usb/uvc/uvc_v4l2.c | 10 +++++++++- drivers/media/usb/uvc/uvcvideo.h | 1 + 2 files changed, 10 insertions(+), 1 deletion(-)