Comment 25 for bug 535476

I can confirm there is something wrong with this USB audio Chipset. The CM106 shows up in lsusb as
"C-Media Electronics, Inc. CM106 Like Sound Device"
It is used in external sound cards etc., offering up to 7.1 audio channles, mic + line in, microphone and headphone connectors. And SPDIF, but I never used that.

On Ubuntu 12.04 (original release) it was recognized and worked. It offered a bunch of profiles, of which I extensively used the '5.1 output only' one. I also tested the mic input and headphone connectors in other profiles: worked. Sometimes upon plugging in the card it was only recognized as stereo capable device or it was recoginizedas 5.1, but the stereo profile had been selected. Adjusting the settings or killing pulseaudio usually worked. Sometimes also the settings for the balancers got lost.
Minor drawback: The card was always set to max volume upon plugging in, no matter what the volume regulator said. Therefore I had to manually switch back to my internal soundcard, then select again the CM106 and finally adjust the volume.

Since some recent kernel upgrade (for ubuntu 12.04, but during spring 2014) this all vanished. I now experience the same problems as described above, with the card being only recognized as stereo device. This applies on current Ubuntu 12.04 versions as well as on Ubuntu 14.04. The problem is not dependent on the other hardware of the computer (checked with four entirely different computers).

As it once worked a fix might be easily possible, but someone with knowledge of pulseaudio has to look into it. Is there any solution in sight?

If anyone is willing to work on this bug I might gladly offer him or her such an device not only for fixing this bug but also as a little reward for the effort.