Public bug reported:
Hardware: ASUS Zenbook S14 UX5406SA (Lunar Lake, CS42L43 codec via SoundWire)
Working kernel: 6.14.0-37-generic
Broken kernel: 6.17.0-14-generic
The ALSA control 'cs42l43 Headphone Digital Volume' has a 2x scaling bug
on kernel 6.17.0-14-generic. The control has a defined range of 0-229,
but after boot it reports a value of 458,458 — exactly double the
maximum. This results in headphone output being effectively silent.
Writing values to the control produces incorrect results. For example,
writing 229 (the defined max) causes the readback to show 0, but the
hardware actually goes to full volume. This makes the control unusable
for both userspace tools and PipeWire/PulseAudio volume management.
The Ubuntu volume slider has no effect on headphone volume because
PipeWire falls back to software volume control, and the hardware volume
is stuck at a bogus level.
Steps to reproduce:
1. Boot kernel 6.17.0-14-generic on ASUS Zenbook S14 UX5406SA
2. Plug in headphones
3. Run: amixer -c 0 cget name='cs42l43 Headphone Digital Volume'
4. Observe values=458,458 with max=229
Expected: values should be within 0-229
Actual: values=458,458
On kernel 6.14.0-37-generic, the same control behaves correctly and
headphones work as expected. This is a regression introduced between
6.14 and 6.17.
Workaround: Manually setting the volume with amixer produces usable
audio but the readback values remain incorrect.
ProblemType: Bug
DistroRelease: Ubuntu 25.10
Package: linux-image-6.17.0-14-generic 6.17.0-14.14
ProcVersionSignature: Ubuntu 6.17.0-14.14-generic 6.17.9
Uname: Linux 6.17.0-14-generic x86_64
ApportVersion: 2.33.1-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: cameron 3124 F.... pipewire
cameron 3136 F.... wireplumber
/dev/snd/seq: cameron 3124 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Wed Mar 11 22:00:54 2026
InstallationDate: Installed on 2025-07-27 (228 days ago)
InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215)
MachineType: ASUSTeK COMPUTER INC. ASUS Zenbook S 14 UX5406SA_UX5406SA
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 xedrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.17.0-14-generic
root=UUID=42cbaac0-0038-40f7-968b-67af2b11480d ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
firmware-sof N/A
linux-firmware 20250901.git993ff19b-0ubuntu1.9
SourcePackage: linux
UpgradeStatus: Upgraded to questing on 2026-03-11 (1 days ago)
dmi.bios.date: 11/08/2024
dmi.bios.release: 5.32
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: UX5406SA.303
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: UX5406SA
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.ec.firmware.release: 3.17
dmi.modalias:
dmi:bvnAmericanMegatrendsInternational,LLC.:bvrUX5406SA.303:bd11/08/2024:br5.32:efr3.17:svnASUSTeKCOMPUTERINC.:pnASUSZenbookS14UX5406SA_UX5406SA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX5406SA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:sku:
dmi.product.family: ASUS Zenbook S 14
dmi.product.name: ASUS Zenbook S 14 UX5406SA_UX5406SA
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug questing wayland-session
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https://bugs.launchpad.net/bugs/2143966
Title:
cs42l43 headphone digital volume scaling bug on kernel
6.17.0-14-generic (ASUS Zenbook S14 UX5406SA)
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