After upgrading from deepin 25.2.2 to 25.3, my external USB audio interface (Steinberg UR44C) completely stopped working for audio playback via PipeWire. The device is detected by the system, and PipeWire creates sink nodes for it, but no audio is heard.

Critically, audio works perfectly when bypassing PipeWire and using ALSA directly (verified with speaker-test -D plughw:0,0). The issue is isolated to PipeWire/WirePlumber.

I have confirmed this is a known upstream ALSA UCM bug (alsa-project/alsa-ucm-conf issue #799), where the UR44C (USB ID 0499:1730) is incorrectly matched to the older UR44 profile (which expects 4 channels instead of 6). The error shown in logs and Bitwig is: spa.alsa: Error in ALSA UCM profile for _ucm0003.hw:UR44C,0 (HiFi: Line2: sink): PlaybackChannels=4 < avail 6.

I have attempted to work around this using custom PipeWire/WirePlumber configuration files in ~/.config/, which worked perfectly in 25.2.2, but they are ignored or overridden in 25.3.

[Steps to Reproduce]

1. Fresh install of deepin 25.2.2 (or upgrade to 25.3).
2. Connect a Steinberg UR44C USB audio interface.
3. Open a terminal and verify the device is detected: aplay -l (shows card 0: UR44C).
4. Attempt to play audio via PipeWire: pw-play /usr/share/sounds/freedesktop/stereo/complete.oga (No sound).
5. Verify hardware works via ALSA: speaker-test -D plughw:0,0 -c 2 (Sine wave is heard, confirming hardware/kernel are fine).
6. Check PipeWire status: wpctl status (Shows the UR44C sink exists and streams are active, but no audio output).

[Log Files]journal_25.2.2_working.txtkernel_journal_25.2.2_working.txt