Hi Alsa development team, First of all: thank you for your great work on the Alsa library. I worked around a problem with the support of the TOSLINK output of my ROG STRIX B650E-I GAMING WIFI motherboard by modifying "/usr/share/alsa/cards/USB-Audio.conf". I made some very crude modifications, just to get it to work. I was not yet able to work out completely how to fix this the proper way. I would appreciate it you could suggest a proper solution. I'd gladly test it and perhaps you'd want to add it to the alsa package. I've attached a zip file with information about the solution and alsa-info.sh output. (As you'll notice in the .asoundrc in attached alsa-info file in, it took me some attempts to solve the issue :-) ). My goal was to have full alsa support, so I could enable a52 encoding through pulseaudio. Thanks, greetings and good luck, Frank Some more background: Initially this command would work: - speaker-test -c2 -t wav -w /usr/share/sounds/alsa/Front_Center.wav -D hw:2,2 But this wouldn't: - speaker-test -c2 -t wav -w /usr/share/sounds/alsa/Front_Center.wav -D plughw:CARD=Audio,DEV=2 This was caused by only these devices reported by "aplay -L" iec958:CARD=Audio,DEV=0 USB Audio, USB Audio IEC958 (S/PDIF) Digital Audio Output iec958:CARD=Audio,DEV=1 USB Audio, USB Audio #1 IEC958 (S/PDIF) Digital Audio Output After the workaround, all 4 devices on my motherboard card are listed: iec958:CARD=Audio,DEV=0 USB Audio, USB Audio IEC958 (S/PDIF) Digital Audio Output iec958:CARD=Audio,DEV=1 USB Audio, USB Audio #1 IEC958 (S/PDIF) Digital Audio Output iec958:CARD=Audio,DEV=2 USB Audio, USB Audio #2 IEC958 (S/PDIF) Digital Audio Output iec958:CARD=Audio,DEV=3 USB Audio, USB Audio #3 IEC958 (S/PDIF) Digital Audio Output Now pulseaudio can support a52 encoding of the 5.1 audiostream to my amplifier (through TOSLINK).