[Bug]: Upstream alsa-ucm-conf regression affecting Turkish locale on Intel Meteor Lake SOF/SoundWire

Read the linked upstream alsa-ucm-conf issue #824 and inspect sof-soundwire.conf, focusing on the locale-dependent expression described there. Reproduce with tr_TR.UTF-8 and check pactl list cards. Done means the installed system exposes the normal HiFi profile instead of only Dummy Output, without changing unrelated audio components.

Kernel

7.1.5-1-cachyos

Desktop Environment / Window Manager

KDE Plasma

CPU

Intel Core Ultra 7 155H

GPU / Driver

Intel Arc Graphics / xe

Description

Summary

This is not a CachyOS-specific bug, but it affects CachyOS users.

Initially the installed system exposed only Dummy Output, while the CachyOS Live ISO worked perfectly on the same hardware.

After a full investigation, the root cause was identified as an upstream alsa-ucm-conf bug.

Upstream issue:

https://github.com/alsa-project/alsa-ucm-conf/issues/824

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Affected hardware

• Acer Swift SFG14-72
• Intel Meteor Lake-P HD Audio (8086:7e28)
• SOF + SoundWire

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Root cause

The issue is caused by a locale-dependent POSIX regular expression in sof-soundwire.conf.

Under tr_TR.UTF-8, ALSA fails to import the UCM profile. As a result, PipeWire/WirePlumber only expose the off profile and the desktop shows Dummy Output.

The problem is not related to PipeWire, WirePlumber, the kernel, firmware or CachyOS packaging itself.

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Suggestion

Until the upstream fix is merged and released, CachyOS could consider carrying the small upstream-compatible patch discussed in the ALSA issue for affected users.

I am happy to test candidate patches or provide additional logs if needed.

Thank you.

Steps to Reproduce

1. Install CachyOS on an Intel Meteor Lake SOF/SoundWire laptop.
2. Use the Turkish locale (tr_TR.UTF-8).
3. Log into KDE Plasma.
4. Open the audio settings or run pactl list cards.

The system exposes only Dummy Output because the HiFi profile is missing.

The same hardware works correctly when booting the CachyOS Live ISO.

Expected Behavior

The installed system should expose the normal HiFi profile, speakers, headphones and internal microphone exactly like the CachyOS Live ISO.

Actual Behavior

The installed system exposes only Dummy Output.

The HiFi profile is missing because ALSA fails to import the SOF SoundWire UCM configuration under tr_TR.UTF-8.

The root cause has been identified as an upstream alsa-ucm-conf issue:

https://github.com/alsa-project/alsa-ucm-conf/issues/824

Logs / Error Messages

No CachyOS-specific logs. The issue has been isolated to an upstream alsa-ucm-conf bug. See upstream report: https://github.com/alsa-project/alsa-ucm-conf/issues/824

Additional Context

The investigation confirmed that:

• The same hardware works correctly with the CachyOS Live ISO.
• The installed system fails only under tr_TR.UTF-8.
• The issue has been fully root-caused and reported upstream.
• A temporary downstream patch could be carried until the upstream fix is released.

Upstream issue:

https://github.com/alsa-project/alsa-ucm-conf/issues/824