Document that Xone:23C needs kernel parameter to work

[christophehenry]

Bug Description

The Allen & Heath Xone:23C is documented to work with Linux but as of now, it isn't natively recognized as a 2 in/2 out audio device by Linux. This kernel ticket documents that the mixer has been correctly recognized somewhere around kernel ~5.4 but most distributions have changed the configuration in /sys/module/usbcore/parameters/old_scheme_first since then.

Currently, on Fedora (and mostly others) the mixer needs the usbcore.old_scheme_first=1 kernel parameter to be correctly recognized, which can be added with the following command-line as root:

grubby --args="usbcore.old_scheme_first=1" --update-kernel=ALL

I opened this ticket to work with the kernel devs to get the mixer to work without the kernel param.

Also, the mixer is documented to need a udev rule, which is not true since #2903 was merged.

Version

Probably all

OS

Linux, probably every distribution running kernel 5.4+