[pulseaudio-discuss] USB Audio: Output only works while mixer is active

[Andreas Böhler]

Hey,

I've got a Phonix Helix Board 12 Universal mixer with integrated
USB/FireWire interface. Using FireWire, it works properly, but using USB
I'm experiencing strange issues which I'm trying to sort out (it should
be UAC2 compliant).

I tested the device with PulseAudio and I observed the following:
Playback through the device only works as long as pavucontrol is
running. If I close pavucontrol, sound output (not playback!) stops
about five seconds later. The player (tested with Audacious) still
plays. As soon as I open pavucontrol, sound output is restored.

I'm not sure whether this is a pulseaudio or ALSA issue, but I'm pretty
certain that, using the list, I can get a clue on what pavucontrol is
doing that keeps my device outputting sound? Does it maybe poll or
output any values on a regular basis? Note that according to alsamixer,
there are no controls available.

Thanks,

Andreas