Missing UCM profile for Realtek ALC4082 USB Audio (26ce:0a08) causing whole-card dropout

Missing UCM profile for Realtek ALC4082 USB Audio (26ce:0a08) causing whole-card dropout

[GitHub issues - opened]

alsa-project/alsa-ucm-conf issue #829 was opened from TIBILL:

**Device:** Realtek ALC4082 USB Audio codec, USB ID 26ce:0a08
**Motherboard:** ASRock X870 Steel Legend WiFi
**Distro:** CachyOS (Arch-based), kernel 7.0.x
**alsa-ucm-conf version:** 1.2.16-2
**PipeWire:** 1.6.6, WirePlumber 0.5.14

**Problem:**
No UCM profile exists for 26ce:0a08. The device falls back to a generic multi-device profile exposing 4 separate PCM playback devices (SPDIF, Speaker 8ch, Headphones, Mic), shown as split sinks (HiFi_7_1__SPDIF__sink, HiFi_7_1__Speaker__sink, HiFi_7_1__Headphones__sink) instead of one clean card profile.

Only one PCM (device 3, S/PDIF output) is actually used. The mixer confirms only one PCM Playback Switch is enabled:
PCM Playback Switch : off
PCM Playback Switch,index=1 : off
PCM Playback Switch,index=2 : on <- the one in use (S/PDIF)

**Symptom:**
Under normal use (browser video, especially transitioning between videos/episodes on streaming sites), the card intermittently gets abandoned by PipeWire and falls back to auto_null. Confirmed NOT a hardware/USB disconnect — dmesg shows no disconnect event for this device during the freeze. Logs at the freeze moment show:
[ERROR:chromium/media/audio/pulse/pulse_util.cc:384] pa_operation is nullptr.
[ERROR:chromium/services/audio/output_device_mixer_impl.cc:173] MixableOutputStream: Error during independent playback

followed by KDE components reporting `No object for name "auto_null"`.

Only fix is a full PipeWire/WirePlumber restart (`systemctl --user restart pipewire pipewire-pulse wireplumber`), which recovers it every time.

Attempting `api.alsa.use-ucm = false` (disabling UCM entirely) results in complete loss of S/PDIF output — so the device requires SOME UCM profile to function at all, but the current generic fallback appears unstable, likely because PipeWire abandons the whole card when one of the 3 unused PCM endpoints fails to prepare (possibly related to PipeWire issue #4938).

**Request:** a proper UCM profile for 26ce:0a08 that only exposes the working PCM device (device 3 / S/PDIF), so the unused Speaker/Headphones/Mic endpoints aren't probed and can't take the whole card down.

**alsa-info.sh output:** [https://termbin.com/cpdns]

Issue URL     : https://github.com/alsa-project/alsa-ucm-conf/issues/829
Repository URL: https://github.com/alsa-project/alsa-ucm-conf