On Wed, Dec 21, 2022 at 10:54:50PM +0000, Mauro Carvalho Chehab wrote: > Em Thu, 22 Dec 2022 00:24:44 +0200 > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> escreveu: > > > Hi Mauro, > > > > On Wed, Dec 21, 2022 at 10:02:48PM +0000, Mauro Carvalho Chehab wrote: > > > Em Tue, 6 Dec 2022 00:02:22 +0100 Ricardo Ribalda escreveu: > > > > On Mon, 5 Dec 2022 at 23:16, Laurent Pinchart wrote: > > > > > On Fri, Dec 02, 2022 at 06:08:19PM +0100, Ricardo Ribalda wrote: > > > > > > Some cameras have multiple data inputs (i.e. IR sensor and RGB sensor), > > > > > > append a unique number to the device name. > > > > > > > > > > > > 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@xxxxxxxxxxxx> > > > > > > --- > > > > > > drivers/media/usb/uvc/uvc_driver.c | 3 ++- > > > > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > > > > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > > > > > index 215fb483efb0..f4032ebb3689 100644 > > > > > > --- a/drivers/media/usb/uvc/uvc_driver.c > > > > > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > > > > > @@ -1963,7 +1963,8 @@ int uvc_register_video_device(struct uvc_device *dev, > > > > > > break; > > > > > > } > > > > > > > > > > > > - strscpy(vdev->name, dev->name, sizeof(vdev->name)); > > > > > > + snprintf(vdev->name, sizeof(vdev->name), "%s %u", dev->name, > > > > > > + stream->header.bTerminalLink); > > > > > > > > > > This won't be perfect as the string is not guaranteed to fit in > > > > > vdev->name, but I suppose it will help as a quick fix for some devices. > > > > > How about the other devices ? Won't they still exhibit the above > > > > > v4l2-compliance failure ? Isn't that something that will still affect > > > > > Chrome OS devices ? > > > > > > > > We could place the id first... but that will look bad: Eg: > > > > > > > > 1- My favorite camera > > > > > > > > Another option is to remove the last chars to fit the id. Eg: > > > > > > > > My favorite came-1 > > > > > > > > If you prefer any of those options or have a better idea I can implement that. > > > > > > > > > The change should not cause any regression as big as in patch 1/3. > > > > > However, unless I'm mistaken users will notice a device name change, > > > > > especially when selecting a device in their web browser. Could that be a > > > > > problem ? > > > > > > > > I think the only side effect is that the first time that the kernel > > > > changes the naming convention, if there are more than one camera on > > > > the system, the video conference might pick a different camera. > > > > The good news is that the user will be presented with cameras with > > > > different names. Now some cameras show very confusing names: > > > > > > > > ribalda@alco:~/work/linux$ for a in /dev/video* ; do yavta -l $a| grep > > > > "Dell Webcam"; done > > > > Device `Dell Webcam WB7022' on `usb-0000:2d:00.0-1.2.3.1' (driver > > > > 'uvcvideo') supports video, capture, without mplanes. > > > > Device `Dell Webcam WB7022' on `usb-0000:2d:00.0-1.2.3.1' (driver > > > > 'uvcvideo') supports meta-data, capture, without mplanes. > > > > Device `Dell Webcam WB7022' on `usb-0000:2d:00.0-1.2.3.1' (driver > > > > 'uvcvideo') supports video, capture, without mplanes. > > > > Device `Dell Webcam WB7022' on `usb-0000:2d:00.0-1.2.3.1' (driver > > > > 'uvcvideo') supports meta-data, capture, without mplanes. > > > > > > That is bad, as some apps like camorama actually store the user > > > preferences (last used resolution and fps), preserving them the next > > > time the camera with the same name is used. > > > > > > In the specific case of camorama, it uses the by-id filename, which is > > > derived from the name, as stored at: > > > > > > $ ls -la /dev/v4l/by-id/usb-Quanta_HD_Camera_0001-video-index* > > > lrwxrwxrwx 1 root root 12 dez 21 09:59 /dev/v4l/by-id/usb-Quanta_HD_Camera_0001-video-index0 -> ../../video0 > > > lrwxrwxrwx 1 root root 12 dez 21 09:59 /dev/v4l/by-id/usb-Quanta_HD_Camera_0001-video-index1 -> ../../video1 > > > > > > With this change, not only the camera name will become bigger (and may > > > end losing the index0/index1 data), but it will also lost the stored > > > preferences on apps like camorama, causing regressions. > > > > > > It sounds a lot easier to teach udev to change the name on an unique > > > way, on machines where you need it. > > > > It's not a udev issue, it's an API compliance problem, entity names in a > > media controller graph must be unique, and they are not. > > Then the right fix would be inside the media controller naming > logic, in a way that it will ensure unique names. It sounds to me > that mc core should then check, at device's register time, if the > name was already used. If so, change it to be unique. The entity name and video device name are one and the same. > > Losing the stored preference is possibly inconvenient in some cases, but > > I don't think it's a real blocker. > > If it causes userspace regressions, then it is a blocker. I wouldn't necessarily call this a regression. -- Regards, Laurent Pinchart
