Hi Devin, On Thursday 25 July 2013 09:11:31 Devin Heitmueller wrote: > On Thu, Jul 25, 2013 at 5:10 AM, Laurent Pinchart wrote: > > Not without dirty hacks. The UVC interfaces don't report whether the > > device has an audio function, the driver would need to look at all the > > interfaces of the parent USB device and find out whether they match one of > > the USB audio drivers. That's not something I would be inclined to merge > > in the uvcvideo driver. > > We need this functionality anyway for other snd-usb-audio based tuners > like em28xx and au0828, so I think some sort of solution is > unavoidable. I hacked something together for em28xx a few years ago > to do such an enumeration, but in reality we should probably have an > export in snd-usb-audio which would help figuring this out in a less > hacky way. > > >> If not, then it looks like the only way to find the associated alsa > >> device is to use libmedia_dev (or its replacement, although I wonder if > >> anyone is still working on that). > > Yup, it's 2013 and we still don't have a way for applications to ask the > kernel which ALSA device is tied to a given /dev/video node. Hans, remember > when I proposed adding a trivial ioctl() call back in 2009 that would allow > this, and you rejected it saying the media controller API was the answer? > It's hard not to feel like salt in the wound that it's four years later and > there *still* isn't a solution. It's partly my fault for not having found time to work on this. http://git.ideasonboard.org/media-ctl.git/shortlog/refs/heads/enum http://git.ideasonboard.org/media-enum.git Not completely there yet, but this already allows enumerating media devices (audio and video) in the system. A bit of code cleanup is still needed in the media-ctl enum branch. I'll try to find time for that next week and finally submit patches. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
