I recently attached my Focusrite Scarlett 2i2 (note: older model than shown here) USB audio interface to my Manjaro desktop.
Generally it seems to be working well, but if I stop / close any applications playing sound, the interface will turn off (power light goes dark) until sound starts playing again. This wouldn’t be a big deal except that my interface is attached to two externally-powered monitors, and whenever the interface starts up again the monitors emit a loud “popping” noise which is probably not great for them.
My initial guess is that this is more of a software thing (eg. deciding to disable the device when it isn’t in use) rather than the audio interface itself, but as I’m fairly new to Linux audio I’m not sure the best place to look. I’m using the XFCE version of Manjaro - not sure if XFCE’s Audio mixer could be the issue or something lower-level (is this a behaviour of PulseAudio / ALSA in general that can be configured? Is it in fact the device itself?).