I'm having an issue with the Microsoft LifeCam Studio in that the camera does not work if the integrated microphone in the camera is activated at the same time. When that happens, the kernel log outputs a variety of warnings such as:

cannot get freq at ep 0x82 ALSA lib pcm_dsnoop.c:614:(snd_pcm_dsnoop_open) unable to open slave uvcvideo: Failed to query (GET_DEF) UVC control 2 on unit 4: -32 (exp. 2). uvcvideo: Failed to query (GET_DEF) UVC control 2 on unit 4: 0 (exp. 2). ALSA lib pcm.c:7980:(snd_pcm_set_params) Channels count (1) not available for CAPTURE: Incorrect argument ALSA lib pcm.c:7956:(snd_pcm_set_params) Broken configuration for CAPTURE: no configurations available ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map uvcvideo: Failed to set UVC probe control : -32 (exp. 26).

There is a workaround in that disabling the built-in microphone by blacklisting snd_usb_audio does make the camera work, but obviously it's not ideal at all, as that way half the camera's functionality is not available and no other USB audio peripherals can be used.

I'm assuming that this is some sort of a quirk in the camera itself; the UVC page ( http://www.ideasonboard.org/uvc/#footnote-13 ) does mention that there is an issue with the bandwidth requests, but setting the 0x80 quirk does not change the situation with the microphone in any way, unfortunately.

I am running the latest mainline kernel (kernel-ml from elrepo) on CentOS 7.1.

Can anything be done about this issue, and is there anything I could do to help debug it?

Also, this issue has been noted a few years back, but it was left unsolved: https://bugs.launchpad.net/ubuntu/+source/guvcview/+bug/1033146 https://sourceforge.net/p/linux-uvc/mailman/message/29645043/ The original reporter said it was a Flash bug, but that is in no way the case because my machine does not have Flash installed to begin with (I'm testing this with WebRTC). -- To unsubscribe from this list: send the line "unsubscribe alsa-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html