diff mbox series

[v3,7/8] media: uvcvideo: Set a different name for the metadata entity

Message ID 20210312124830.1344255-8-ribalda@chromium.org (mailing list archive)
State New, archived
Headers show
Series Fix v4l2-compliance errors | expand

Commit Message

Ricardo Ribalda March 12, 2021, 12:48 p.m. UTC
All the entities must have a unique name. And now that we are at it, we
append the entity->id to the name to avoid collisions on 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>
---
 drivers/media/usb/uvc/uvc_driver.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

Comments

Laurent Pinchart March 12, 2021, 10:27 p.m. UTC | #1
Hi Ricardo,

Thank you for the patch.

On Fri, Mar 12, 2021 at 01:48:29PM +0100, Ricardo Ribalda wrote:
> All the entities must have a unique name. And now that we are at it, we
> append the entity->id to the name to avoid collisions on 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>
> ---
>  drivers/media/usb/uvc/uvc_driver.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 35873cf2773d..6c928e708615 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -2154,6 +2154,18 @@ static void uvc_unregister_video(struct uvc_device *dev)
>  #endif
>  }
>  
> +static int uvc_oterm_id(struct uvc_video_chain *chain)
> +{
> +	struct uvc_entity *entity;
> +
> +	list_for_each_entry(entity, &chain->entities, chain) {
> +		if (UVC_ENTITY_IS_OTERM(entity))
> +			return entity->id;

It can also be an ITERM for output devices. You can drop this function
and use stream>header.bTerminalLink below (see uvc_stream_by_id() and
its usage in uvc_register_terms()).

> +	}
> +
> +	return -1;
> +}
> +
>  int uvc_register_video_device(struct uvc_device *dev,
>  			      struct uvc_streaming *stream,
>  			      struct video_device *vdev,
> @@ -2162,6 +2174,8 @@ int uvc_register_video_device(struct uvc_device *dev,
>  			      const struct v4l2_file_operations *fops,
>  			      const struct v4l2_ioctl_ops *ioctl_ops)
>  {
> +	char prefix[sizeof(vdev->name) - 9];
> +	const char *suffix;
>  	int ret;
>  
>  	/* Initialize the video buffers queue. */
> @@ -2190,16 +2204,21 @@ 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;
> +		suffix = "video";
>  		break;
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
>  		vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
> +		suffix = "out";

I wonder if these two should be video-cap and video-out (or vid-cap and
vid-out if you want to shorten them) ?

>  		break;
>  	case V4L2_BUF_TYPE_META_CAPTURE:
>  		vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> +		suffix = "meta";
>  		break;
>  	}
>  
> -	strscpy(vdev->name, dev->name, sizeof(vdev->name));
> +	strscpy(prefix, dev->name, sizeof(prefix));
> +	snprintf(vdev->name, sizeof(vdev->name), "%s-%d %s", prefix,

The unit ID is never negative, so %u ?

> +		 uvc_oterm_id(stream->chain), suffix);

Truncating the device name at the beginning of the video node name isn't
very nice :-S How about the following ?

	snprintf(vdev->name, sizeof(vdev->name), "%s-%u (%s)", type_name,
		 uvc_oterm_id(stream->chain), dev->name);

with the suffix variable renamed to type_name ?

Thinking some more about it, vdev->name serves two purposes in the
driver: creating the entity name, and reporting the card name in
querycap. The former is done in the V4L2 core, which uses vdev->name
as-is. In this context, we con't need to add dev->name, it would be
redundant as the media controller device already reports it. The latter
is done in uvc_ioctl_querycap(). How about dropping dev->name from
vdev->name, and modifying uvc_ioctl_querycap() to use dev->name instead
of cap->card ?

>  
>  	/*
>  	 * Set the driver data before calling video_register_device, otherwise
Ricardo Ribalda Delgado March 12, 2021, 11:17 p.m. UTC | #2
HI Laurent

Thanks for the review

On Fri, Mar 12, 2021 at 11:30 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.
>
> On Fri, Mar 12, 2021 at 01:48:29PM +0100, Ricardo Ribalda wrote:
> > All the entities must have a unique name. And now that we are at it, we
> > append the entity->id to the name to avoid collisions on 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>
> > ---
> >  drivers/media/usb/uvc/uvc_driver.c | 21 ++++++++++++++++++++-
> >  1 file changed, 20 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index 35873cf2773d..6c928e708615 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -2154,6 +2154,18 @@ static void uvc_unregister_video(struct uvc_device *dev)
> >  #endif
> >  }
> >
> > +static int uvc_oterm_id(struct uvc_video_chain *chain)
> > +{
> > +     struct uvc_entity *entity;
> > +
> > +     list_for_each_entry(entity, &chain->entities, chain) {
> > +             if (UVC_ENTITY_IS_OTERM(entity))
> > +                     return entity->id;
>
> It can also be an ITERM for output devices. You can drop this function
> and use stream>header.bTerminalLink below (see uvc_stream_by_id() and
> its usage in uvc_register_terms()).
>
> > +     }
> > +
> > +     return -1;
> > +}
> > +
> >  int uvc_register_video_device(struct uvc_device *dev,
> >                             struct uvc_streaming *stream,
> >                             struct video_device *vdev,
> > @@ -2162,6 +2174,8 @@ int uvc_register_video_device(struct uvc_device *dev,
> >                             const struct v4l2_file_operations *fops,
> >                             const struct v4l2_ioctl_ops *ioctl_ops)
> >  {
> > +     char prefix[sizeof(vdev->name) - 9];
> > +     const char *suffix;
> >       int ret;
> >
> >       /* Initialize the video buffers queue. */
> > @@ -2190,16 +2204,21 @@ 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;
> > +             suffix = "video";
> >               break;
> >       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >               vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
> > +             suffix = "out";
>
> I wonder if these two should be video-cap and video-out (or vid-cap and
> vid-out if you want to shorten them) ?
>
> >               break;
> >       case V4L2_BUF_TYPE_META_CAPTURE:
> >               vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> > +             suffix = "meta";
> >               break;
> >       }
> >
> > -     strscpy(vdev->name, dev->name, sizeof(vdev->name));
> > +     strscpy(prefix, dev->name, sizeof(prefix));
> > +     snprintf(vdev->name, sizeof(vdev->name), "%s-%d %s", prefix,
>
> The unit ID is never negative, so %u ?
>
> > +              uvc_oterm_id(stream->chain), suffix);
>
> Truncating the device name at the beginning of the video node name isn't
> very nice :-S How about the following ?
>
>         snprintf(vdev->name, sizeof(vdev->name), "%s-%u (%s)", type_name,
>                  uvc_oterm_id(stream->chain), dev->name);
>
> with the suffix variable renamed to type_name ?
>
> Thinking some more about it, vdev->name serves two purposes in the
> driver: creating the entity name, and reporting the card name in
> querycap. The former is done in the V4L2 core, which uses vdev->name
> as-is. In this context, we con't need to add dev->name, it would be
> redundant as the media controller device already reports it. The latter
> is done in uvc_ioctl_querycap(). How about dropping dev->name from
> vdev->name, and modifying uvc_ioctl_querycap() to use dev->name instead
> of cap->card ?
>

Something like ?
https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=d4f7363455837116268152c96bf4b78d9761ad1e
https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=ee3916f12b30f56c03d5622ba8a599b9c610a055

I need to work on the V4L2_CTRL_FLAG_GRABBED issue and then I will
send the whole v4 series that can pass all the v4l2-compliance test :)

Thanks!

> >
> >       /*
> >        * Set the driver data before calling video_register_device, otherwise
>
> --
> Regards,
>
> Laurent Pinchart
Laurent Pinchart March 12, 2021, 11:28 p.m. UTC | #3
Hi Ricardo,

On Sat, Mar 13, 2021 at 12:17:50AM +0100, Ricardo Ribalda Delgado wrote:
> On Fri, Mar 12, 2021 at 11:30 PM Laurent Pinchart wrote:
> > On Fri, Mar 12, 2021 at 01:48:29PM +0100, Ricardo Ribalda wrote:
> > > All the entities must have a unique name. And now that we are at it, we
> > > append the entity->id to the name to avoid collisions on 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>
> > > ---
> > >  drivers/media/usb/uvc/uvc_driver.c | 21 ++++++++++++++++++++-
> > >  1 file changed, 20 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > > index 35873cf2773d..6c928e708615 100644
> > > --- a/drivers/media/usb/uvc/uvc_driver.c
> > > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > > @@ -2154,6 +2154,18 @@ static void uvc_unregister_video(struct uvc_device *dev)
> > >  #endif
> > >  }
> > >
> > > +static int uvc_oterm_id(struct uvc_video_chain *chain)
> > > +{
> > > +     struct uvc_entity *entity;
> > > +
> > > +     list_for_each_entry(entity, &chain->entities, chain) {
> > > +             if (UVC_ENTITY_IS_OTERM(entity))
> > > +                     return entity->id;
> >
> > It can also be an ITERM for output devices. You can drop this function
> > and use stream>header.bTerminalLink below (see uvc_stream_by_id() and
> > its usage in uvc_register_terms()).
> >
> > > +     }
> > > +
> > > +     return -1;
> > > +}
> > > +
> > >  int uvc_register_video_device(struct uvc_device *dev,
> > >                             struct uvc_streaming *stream,
> > >                             struct video_device *vdev,
> > > @@ -2162,6 +2174,8 @@ int uvc_register_video_device(struct uvc_device *dev,
> > >                             const struct v4l2_file_operations *fops,
> > >                             const struct v4l2_ioctl_ops *ioctl_ops)
> > >  {
> > > +     char prefix[sizeof(vdev->name) - 9];
> > > +     const char *suffix;
> > >       int ret;
> > >
> > >       /* Initialize the video buffers queue. */
> > > @@ -2190,16 +2204,21 @@ 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;
> > > +             suffix = "video";
> > >               break;
> > >       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> > >               vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
> > > +             suffix = "out";
> >
> > I wonder if these two should be video-cap and video-out (or vid-cap and
> > vid-out if you want to shorten them) ?
> >
> > >               break;
> > >       case V4L2_BUF_TYPE_META_CAPTURE:
> > >               vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> > > +             suffix = "meta";
> > >               break;
> > >       }
> > >
> > > -     strscpy(vdev->name, dev->name, sizeof(vdev->name));
> > > +     strscpy(prefix, dev->name, sizeof(prefix));
> > > +     snprintf(vdev->name, sizeof(vdev->name), "%s-%d %s", prefix,
> >
> > The unit ID is never negative, so %u ?
> >
> > > +              uvc_oterm_id(stream->chain), suffix);
> >
> > Truncating the device name at the beginning of the video node name isn't
> > very nice :-S How about the following ?
> >
> >         snprintf(vdev->name, sizeof(vdev->name), "%s-%u (%s)", type_name,
> >                  uvc_oterm_id(stream->chain), dev->name);
> >
> > with the suffix variable renamed to type_name ?
> >
> > Thinking some more about it, vdev->name serves two purposes in the
> > driver: creating the entity name, and reporting the card name in
> > querycap. The former is done in the V4L2 core, which uses vdev->name
> > as-is. In this context, we con't need to add dev->name, it would be
> > redundant as the media controller device already reports it. The latter
> > is done in uvc_ioctl_querycap(). How about dropping dev->name from
> > vdev->name, and modifying uvc_ioctl_querycap() to use dev->name instead
> > of cap->card ?
> >
> 
> Something like ?
> https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=d4f7363455837116268152c96bf4b78d9761ad1e

I would have moved the sprintf() after the switch/case, but otherwise
it's the idea.

> https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=ee3916f12b30f56c03d5622ba8a599b9c610a055

Looks good.

> I need to work on the V4L2_CTRL_FLAG_GRABBED issue and then I will
> send the whole v4 series that can pass all the v4l2-compliance test :)
> 
> > >
> > >       /*
> > >        * Set the driver data before calling video_register_device, otherwise
Ricardo Ribalda Delgado March 12, 2021, 11:47 p.m. UTC | #4
Hi Laurent

Thanks!
On Sat, Mar 13, 2021 at 12:29 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> On Sat, Mar 13, 2021 at 12:17:50AM +0100, Ricardo Ribalda Delgado wrote:
> > On Fri, Mar 12, 2021 at 11:30 PM Laurent Pinchart wrote:
> > > On Fri, Mar 12, 2021 at 01:48:29PM +0100, Ricardo Ribalda wrote:
> > > > All the entities must have a unique name. And now that we are at it, we
> > > > append the entity->id to the name to avoid collisions on 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>
> > > > ---
> > > >  drivers/media/usb/uvc/uvc_driver.c | 21 ++++++++++++++++++++-
> > > >  1 file changed, 20 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > > > index 35873cf2773d..6c928e708615 100644
> > > > --- a/drivers/media/usb/uvc/uvc_driver.c
> > > > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > > > @@ -2154,6 +2154,18 @@ static void uvc_unregister_video(struct uvc_device *dev)
> > > >  #endif
> > > >  }
> > > >
> > > > +static int uvc_oterm_id(struct uvc_video_chain *chain)
> > > > +{
> > > > +     struct uvc_entity *entity;
> > > > +
> > > > +     list_for_each_entry(entity, &chain->entities, chain) {
> > > > +             if (UVC_ENTITY_IS_OTERM(entity))
> > > > +                     return entity->id;
> > >
> > > It can also be an ITERM for output devices. You can drop this function
> > > and use stream>header.bTerminalLink below (see uvc_stream_by_id() and
> > > its usage in uvc_register_terms()).
> > >
> > > > +     }
> > > > +
> > > > +     return -1;
> > > > +}
> > > > +
> > > >  int uvc_register_video_device(struct uvc_device *dev,
> > > >                             struct uvc_streaming *stream,
> > > >                             struct video_device *vdev,
> > > > @@ -2162,6 +2174,8 @@ int uvc_register_video_device(struct uvc_device *dev,
> > > >                             const struct v4l2_file_operations *fops,
> > > >                             const struct v4l2_ioctl_ops *ioctl_ops)
> > > >  {
> > > > +     char prefix[sizeof(vdev->name) - 9];
> > > > +     const char *suffix;
> > > >       int ret;
> > > >
> > > >       /* Initialize the video buffers queue. */
> > > > @@ -2190,16 +2204,21 @@ 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;
> > > > +             suffix = "video";
> > > >               break;
> > > >       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> > > >               vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
> > > > +             suffix = "out";
> > >
> > > I wonder if these two should be video-cap and video-out (or vid-cap and
> > > vid-out if you want to shorten them) ?
> > >
> > > >               break;
> > > >       case V4L2_BUF_TYPE_META_CAPTURE:
> > > >               vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> > > > +             suffix = "meta";
> > > >               break;
> > > >       }
> > > >
> > > > -     strscpy(vdev->name, dev->name, sizeof(vdev->name));
> > > > +     strscpy(prefix, dev->name, sizeof(prefix));
> > > > +     snprintf(vdev->name, sizeof(vdev->name), "%s-%d %s", prefix,
> > >
> > > The unit ID is never negative, so %u ?
> > >
> > > > +              uvc_oterm_id(stream->chain), suffix);
> > >
> > > Truncating the device name at the beginning of the video node name isn't
> > > very nice :-S How about the following ?
> > >
> > >         snprintf(vdev->name, sizeof(vdev->name), "%s-%u (%s)", type_name,
> > >                  uvc_oterm_id(stream->chain), dev->name);
> > >
> > > with the suffix variable renamed to type_name ?
> > >
> > > Thinking some more about it, vdev->name serves two purposes in the
> > > driver: creating the entity name, and reporting the card name in
> > > querycap. The former is done in the V4L2 core, which uses vdev->name
> > > as-is. In this context, we con't need to add dev->name, it would be
> > > redundant as the media controller device already reports it. The latter
> > > is done in uvc_ioctl_querycap(). How about dropping dev->name from
> > > vdev->name, and modifying uvc_ioctl_querycap() to use dev->name instead
> > > of cap->card ?
> > >
> >
> > Something like ?
> > https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=d4f7363455837116268152c96bf4b78d9761ad1e
>
> I would have moved the sprintf() after the switch/case, but otherwise
> it's the idea.

https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=fe287f9d764457f5bcd48780b99e54df161f33f6

Yep, it looks better

>
> > https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-compliance-v4&id=ee3916f12b30f56c03d5622ba8a599b9c610a055
>
> Looks good.
>
> > I need to work on the V4L2_CTRL_FLAG_GRABBED issue and then I will
> > send the whole v4 series that can pass all the v4l2-compliance test :)
> >
> > > >
> > > >       /*
> > > >        * Set the driver data before calling video_register_device, otherwise
>
> --
> Regards,
>
> Laurent Pinchart
diff mbox series

Patch

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 35873cf2773d..6c928e708615 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2154,6 +2154,18 @@  static void uvc_unregister_video(struct uvc_device *dev)
 #endif
 }
 
+static int uvc_oterm_id(struct uvc_video_chain *chain)
+{
+	struct uvc_entity *entity;
+
+	list_for_each_entry(entity, &chain->entities, chain) {
+		if (UVC_ENTITY_IS_OTERM(entity))
+			return entity->id;
+	}
+
+	return -1;
+}
+
 int uvc_register_video_device(struct uvc_device *dev,
 			      struct uvc_streaming *stream,
 			      struct video_device *vdev,
@@ -2162,6 +2174,8 @@  int uvc_register_video_device(struct uvc_device *dev,
 			      const struct v4l2_file_operations *fops,
 			      const struct v4l2_ioctl_ops *ioctl_ops)
 {
+	char prefix[sizeof(vdev->name) - 9];
+	const char *suffix;
 	int ret;
 
 	/* Initialize the video buffers queue. */
@@ -2190,16 +2204,21 @@  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;
+		suffix = "video";
 		break;
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
 		vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
+		suffix = "out";
 		break;
 	case V4L2_BUF_TYPE_META_CAPTURE:
 		vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
+		suffix = "meta";
 		break;
 	}
 
-	strscpy(vdev->name, dev->name, sizeof(vdev->name));
+	strscpy(prefix, dev->name, sizeof(prefix));
+	snprintf(vdev->name, sizeof(vdev->name), "%s-%d %s", prefix,
+		 uvc_oterm_id(stream->chain), suffix);
 
 	/*
 	 * Set the driver data before calling video_register_device, otherwise