Hi Nicolas,

On Mon, Dec 06, 2021 at 02:05:06PM -0500, Nicolas Dufresne wrote:

Le vendredi 18 juin 2021 à 14:29 +0200, Ricardo Ribalda a écrit :

...

All the entities must have a unique name. We can have a descriptive and unique name by appending the function and the entity->id.

Thanks for your work. The only issue is that unfortunately this change cause an important regression for users. All UVC cameras in all UIs seems to no longer include any information about the camera. As an example, I have two cameras on my system and Firefox, Chrome, Cheese, Zoom and MS Team all agree that my camera are now:

Video Capture 4 Video Capture 5

Previously they would be shown as something like:

StreamCam Integrated

We should probably revert this change quickly before it get deployed more widely, I have notice the backport being sent for 5.4, 5.10 and 5.14. I'm using 5.15 shipped by Fedora team.

Ack.

As a proper solution, maybe I could suggest to keep using dev->name, but trim it enough to fit the " N" string to guaranty that you have enough space in this limited 32 char string and use that instead ? This should fit the uniqueness requirement without the sacrifice of the only possibly useful information we had in that limited string.

That would polute the device name a bit, which isn't very nice for users. I wonder if we could instead decouple the entity name from the video device name.

...

This is even resilent to multi chain devices.

Fixes v4l2-compliance: Media Controller ioctls: fail: v4l2-test-media.cpp(205): v2_entity_names_set.find(key) != v2_entity_names_set.end() test MEDIA_IOC_G_TOPOLOGY: FAIL fail: v4l2-test-media.cpp(394): num_data_links != num_links test MEDIA_IOC_ENUM_ENTITIES/LINKS: FAIL

Signed-off-by: Ricardo Ribalda ribalda@chromium.org Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Reviewed-by: Hans Verkuil hverkuil-cisco@xs4all.nl

---

drivers/media/usb/uvc/uvc_driver.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 14b60792ffab..037bf80d1100 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -2194,6 +2194,7 @@ int uvc_register_video_device(struct uvc_device *dev, const struct v4l2_file_operations *fops, const struct v4l2_ioctl_ops *ioctl_ops) {

• const char *name; int ret;

/* Initialize the video buffers queue. */ @@ -2222,16 +2223,20 @@ int uvc_register_video_device(struct uvc_device *dev, case V4L2_BUF_TYPE_VIDEO_CAPTURE: default: vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;

• name = "Video Capture";
  

  break; case V4L2_BUF_TYPE_VIDEO_OUTPUT: vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;

• name = "Video Output";
  

  break; case V4L2_BUF_TYPE_META_CAPTURE: vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;

• name = "Metadata";
  

  break; }

• strscpy(vdev->name, dev->name, sizeof(vdev->name));

• snprintf(vdev->name, sizeof(vdev->name), "%s %u", name,

•  stream->header.bTerminalLink);
  

/* * Set the driver data before calling video_register_device, otherwise