I have been trying to work on a fix for Bug 1498129 - https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1498129 on Ubuntu

My USB soundcard is an Asus Xonar U7 Echelon Edition https://www.asus.com/Sound-Cards/Xonar_U7_Echelon_Edition/ which identifies itself to alsa as "Xonar U7 Echelon Ed." The card is supported by alsa and works well in analog mode but I cannot get digital output via alsa or pulseaudio.

It has iec958 as device 1 rather than device 0 and I can access digital output by referring to directly to hw:x,1 but cannot access digital output via alsa.

The fix I believe is to add "Xonar U7 Echelon Ed." 1 to the USB-Audio.pcm.iec958_device section of USB-Audio.conf. This does not work. As I suspected, and now have confirmed by Raymond on the bug report, this is because the alsa name for this card contains the period character '.'

Is there a workaround for this or do I need to await an alsa code change?