Missing UCM profile for Fifine SC3 (3142:0c33) causes PCM volume to reset to 0 on every boot

[GitHub issues - opened <github@alsa-project.org>]

alsa-project/alsa-ucm-conf issue #788 was opened from jacxel42:

> Note: This issue description was drafted with the help of an AI assistant based on troubleshooting steps and command output from my system. I've done a cursory check and believe it's accurate, but I'm not very familiar with ALSA/UCM internals, so please let me know if anything doesn't make sense or needs clarifying — happy to run further commands or tests.

### Summary

The Fifine SC3 USB audio interface (`3142:0c33`) has no UCM profile (`ucm2/USB-Audio/conf.d/3142-0c33.conf` does not exist). As a result, `alsa-restore.service` fails to restore the saved PCM mixer state on boot, and the `PCM` playback volume defaults to `0` every time the system starts — effectively muting the device until manually corrected.

### Hardware

- Device: Fifine SC3 (USB audio mixer/interface)
- USB ID: `3142:0c33` (MV-SILICON)
- `aplay -l` shows it as `card 1: SC3 [fifine SC3], device 0: USB Audio [USB Audio]`

### Symptom

On every boot:
- `alsamixer -c SC3` shows `PCM` at `0`
- Desktop volume controls appear functional (volume slider moves, mute toggle works) but produce no audible output, because the underlying ALSA PCM level is at 0 regardless of what PipeWire/WirePlumber report
- Manually running `alsamixer` and raising `PCM` to `100` immediately restores audio, but this does not persist across reboots

### Root cause

`alsa-restore.service` logs the following on every boot:

```
alsa-lib utils.c:372:(uc_mgr_config_load_into) could not open configuration file /usr/share/alsa/ucm2/USB-Audio/conf.d/3142-0c33.conf
alsa-lib parser.c:79:(uc_mgr_config_load_file) failed to open file /usr/share/alsa/ucm2/USB-Audio/conf.d/3142-0c33.conf: -2
```

Because no UCM profile exists for this device, `alsactl restore` does not properly initialise/restore the `PCM` mixer control, even though `alsactl store` correctly saves `PCM Playback Volume` at the desired level (4096/4096, 100%) in `/var/lib/alsa/asound.state`.

### Confirmed simple mixer controls

```
$ amixer -c SC3 scontrols
Simple mixer control 'PCM',0
Simple mixer control 'Mic',0

$ amixer -c SC3 controls
numid=3,iface=MIXER,name='PCM Playback Switch'
numid=4,iface=MIXER,name='PCM Playback Volume'
numid=5,iface=MIXER,name='Mic Capture Switch'
numid=6,iface=MIXER,name='Mic Capture Volume'
numid=2,iface=PCM,name='Capture Channel Map'
numid=1,iface=PCM,name='Playback Channel Map'
```

### Current workaround

A udev rule that runs `amixer -c SC3 sset 'PCM' 100%` whenever the device is detected (`ACTION=="add", SUBSYSTEM=="sound", ATTRS{idVendor}=="3142", ATTRS{idProduct}=="0c33"`) resolves the issue, but a proper UCM profile would fix this for all users without requiring a manual workaround.

### Environment

- OS: Bazzite Linux (Fedora Atomic / Universal Blue based)
- Audio stack: PipeWire + WirePlumber (device runs in pro-audio profile)

### Request

Could a UCM profile be added for `3142:0c33` (Fifine SC3) that correctly initialises/restores the `PCM` mixer control on boot? Full `alsa-info.sh` output attached/linked separately. Happy to test any proposed config.


[alsa-info.txt](https://github.com/user-attachments/files/28919510/alsa-info.txt)

Issue URL     : https://github.com/alsa-project/alsa-ucm-conf/issues/788
Repository URL: https://github.com/alsa-project/alsa-ucm-conf