Hello all,
I own this card since recently:
03:00.0 Audio device: C-Media Electronics Inc CM8888 [Oxygen Express] Subsystem: C-Media Electronics Inc HDA Controller Flags: bus master, fast devsel, latency 0, IRQ 31, IOMMU group 7 Memory at fcd00000 (32-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: snd_hda_intel Kernel modules: snd_hda_intel
and I found out it doesn't work great. Only headphone output is functioning, RCA line out does not (haven't checked the rest). I found models list in /usr/lib/modules/5.9.2-arch1-1/build/Documentation/sound/hd-audio/models.rst and tested them all using a rmmod / modprobe bash script but none of them seems to enable RCA output.
Windows drivers have possibility to switch between headphone and RCA output from manufacturer's app (there is a click sound coming from electronics of the card when I do this).
I never tampered with low level hardware and I'm not familiar with ALSA development but what I was thinking is that maybe an ALSA snd_hda_intel developer would be interested in receiving this card for tests?