On 2019-04-27, Christian Weisgerber <na...@mips.inka.de> wrote: > It is my theoretical understanding that USB audio gadgets typically > come with a uhid(4) device, as does yours above, and you would use > usbhidctl(1) to list and manipulate the available controls.
No, that is wrong. Looking over uaudio.c, I now see that mixer controls are an inherent part of the USB audio spec and that the driver automatically provides them. So the correct answer is this: If your USB audio gadget attaches as audioN, use "mixerctl -f /dev/mixerN" to access the corresponding controls. If you don't specify a device, mixerctl uses /dev/mixer, which by default is a symlink to /dev/mixer0. You can point this symlink to a different unit. Alternatively, you can set MIXERDEVICE in the enironment. (Personally, I have only used USB audio dongles to add an S/PDIF output to machines that lacked one, so the mixer didn't really come up.) -- Christian "naddy" Weisgerber na...@mips.inka.de
