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usb: gadget: uvc: disable stream when disconnected

PATCH New Laurent Pinchart 1 participant 1 message May 21, 2018 USB

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Laurent Pinchart

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PATCH v2 3/3 usb: gadget: uvc: disable stream when disconnected

Hi Paul,

Thank you for the patch.

Quoted 22 lines · On Tuesday, 24 April 2018 23:59:36 EEST Paul Elder wrote:

Down the call stack from the ioctl handler for VIDIOC_STREAMON, uvc_video_alloc_requests contains a BUG_ON, which in the high level, triggers when VIDIOC_STREAMON ioctl is issued without VIDIOC_STREAMOFF being issued previously.

This can also be triggered by starting the stream and then physically disconnecting usb. To fix this, do the streamoff procedures on usb disconnect.

Signed-off-by Paul Elder <[email protected]>

---
Changes in v2: Nothing

 drivers/usb/gadget/function/f_uvc.c | 3 +++
 1 file changed, 3 insertions(+)
(quoted diff) +0 -0

b/drivers/usb/gadget/function/f_uvc.c index fa34dcbe1197..5bb79888e3f7 100644

drivers/usb/gadget/function/f_uvc.c uvc_function_disable(struct usb_function *f) · line 382

Quoted 9 lines
drivers/usb/gadget/function/f_uvc.c +3 -0
@@ -374,9 +374,12 @@ uvc_function_disable(struct usb_function *f)
 {
 	struct uvc_device *uvc = to_uvc(f);
 	struct v4l2_event v4l2_event;
+	struct uvc_video *video = &uvc->video;
 
 	INFO(f->config->cdev, "uvc_function_disable\n");
 
+	uvcg_video_enable(video, 0);
+

As commented in my reply to patch 2/3, you will need to protect this with proper locking. You now have at least four events dealing with states and buffers allocation (VIDIOC_STREAMON, VIDIOC_STREAMOFF, uvc_function_set_alt and uvc_function_disable).

Quoted 3 lines
drivers/usb/gadget/function/f_uvc.c +0 -0
 	memset(&v4l2_event, 0, sizeof(v4l2_event));
 	v4l2_event.type = UVC_EVENT_DISCONNECT;
 	v4l2_event_queue(&uvc->vdev, &v4l2_event);