alsa-project/alsa-lib issue #303 was opened from molli1312:

Having a few problems with the Xone32c though not sure if this is an ALSA issue or general USB stack problem.

It's a USB soundcard that is supposed to have 4 inputs and 4 outputs. It seems to have 2 USB configurations (bNumConfigurations : 0x2). When plugged in, bConfigurationValue is 0x1 and only 2 inputs and 2 outputs show up. Change this value to 0x2 and it shows up (as it should) as 4 inputs and 4 outputs.

I can change the bConfigurationValue with this udev rule, or with a `echo 2

/sys/bus/usb/devices/1-1.4/bConfigurationValue`:

This has all been working OK on Ubuntu 20.04 running kernel 5.4.0-33-generic. However, I just updated to 5.4.0-37-generic and now there is only a single USB configuration (bNumConfigurations : 0x1) and bConfigurationValue can't be changed to 0x2:

Issue URL : https://github.com/alsa-project/alsa-lib/issues/303 Repository URL: https://github.com/alsa-project/alsa-lib