Public bug reported:
# Bug Report: Realtek ALC257 speaker mute LED not exposed via `ctl-led`
on Lenovo (17aa:3802) with SOF driver
## Summary
On a Lenovo laptop with Realtek ALC257 codec and Intel Meteor Lake SOF
audio driver (`sof-audio-pci-intel-mtl`), the **speaker mute LED is not
registered as a controllable LED** in the kernel's `ctl-led` framework.
As a result, the mute LED never lights up when audio is muted via
`Fn+F1`.
The **microphone mute LED works correctly**, and `ctl-led/mic/card0/`
exposes `attach`/`detach`/`list`. In contrast, `ctl-led/speaker/card0/`
has **no `attach` file at all**, only `brightness`, `mode`, `power`, and
`uevent`. This indicates the speaker LED was registered as a generic LED
but **not** as an audio-controllable LED.
## Environment
- **Distro**: Ubuntu 26.04
- **Kernel**: `7.0.0-38-generic #38-Ubuntu SMP PREEMPT_DYNAMIC Fri Sep 4
09:10:14 UTC 2026 x86_64 GNU/Linux`
- **Machine**: Lenovo (SSID `17aa:3802`)
- **Audio codec**: Realtek ALC257
- **Audio driver stack**:
- `sof-audio-pci-intel-mtl 0000:00:1f.3`
- `snd_hda_codec_alc269` (ALC257 fixup picked for PCI SSID 17aa:3802)
- `skl_hda_dsp_generic`
- Topology: `intel/sof-ipc4-tplg/sof-hda-generic-2ch.tplg`
## Steps to Reproduce
1. Boot Ubuntu 26.04 on this Lenovo machine.
2. Confirm microphone mute LED works: press mic mute key (e.g. F4) — LED
toggles correctly.
3. Press `Fn+F1` to toggle speaker mute. Audio mutes/unmutes correctly, but the
**speaker mute LED never changes state**.
## Observed Behavior
### `ls -l /sys/class/sound/ctl-led/`
```
total 0
drwxr-xr-x 4 root root 0 Oct 8 14:50 mic
drwxr-xr-x 2 root root 0 Oct 8 14:50 power
drwxr-xr-x 4 root root 0 Oct 8 14:50 speaker
lrwxrwxrwx 1 root root 0 Oct 8 06:22 subsystem -> ../../../../class/sound
-rw-r--r-- 1 root root 4096 Oct 8 14:50 uevent
```
### `ls -l /sys/class/sound/ctl-led/speaker/card0/`
```
total 0
-r--r--r-- 1 root root 4096 Oct 8 15:00 brightness
drwxr-xr-x 3 root root 0 Oct 8 14:51 card0
-rw-r--r-- 1 root root 4096 Oct 8 15:00 mode
drwxr-xr-x 2 root root 0 Oct 8 15:00 power
-rw-r--r-- 1 root root 4096 Oct 8 15:00 uevent
```
**Note**: There is **no `attach`, `detach`, or `list`** file in
`speaker/card0/`, unlike `mic/card0/`.
### `ls -l /sys/class/sound/ctl-led/mic/card*/`
```
total 0
--w------- 1 root root 4096 Oct 8 14:51 attach
lrwxrwxrwx 1 root root 0 Oct 8 14:51 card ->
../../../../../pci0000:00/0000:00:1f.3/skl_hda_dsp_generic/sound/card0
--w------- 1 root root 4096 Oct 8 06:22 detach
-r--r--r-- 1 root root 4096 Oct 8 14:51 list
drwxr-xr-x 2 root root 0 Oct 8 14:51 power
--w------- 1 root root 4096 Oct 8 14:51 reset
-rw-r--r-- 1 root root 4096 Oct 8 14:51 uevent
```
### `cat /sys/class/sound/ctl-led/mic/card0/list`
```
49
```
`numid=49` corresponds to:
```
numid=49,iface=MIXER,name='Dmic0 Capture Switch'
```
So the microphone LED is auto-bound to `Dmic0 Capture Switch`.
### `cat /sys/class/sound/ctl-led/speaker/card0/list`
```
(empty)
```
### `amixer -c 0 controls | grep -i -E "master|speaker|mute|switch"`
```
numid=13,iface=CARD,name='Speaker Phantom Jack'
numid=10,iface=MIXER,name='Master Playback Switch'
numid=9,iface=MIXER,name='Master Playback Volume'
numid=2,iface=MIXER,name='Headphone Playback Switch'
numid=7,iface=MIXER,name='Capture Switch'
numid=18,iface=MIXER,name='IEC958 Playback Switch'
numid=24,iface=MIXER,name='IEC958 Playback Switch',index=1
numid=30,iface=MIXER,name='IEC958 Playback Switch',index=2
numid=5,iface=MIXER,name='Auto-Mute Mode'
numid=46,iface=MIXER,name='Dmic0 Capture DRC switch'
numid=49,iface=MIXER,name='Dmic0 Capture Switch'
numid=43,iface=MIXER,name='Dmic0 Capture TDFB beam switch'
numid=40,iface=MIXER,name='Post Mixer Analog Playback DRC switch'
numid=4,iface=MIXER,name='Speaker Playback Switch'
numid=3,iface=MIXER,name='Speaker Playback Volume'
```
**Relevant controls exist** (`Master Playback Switch` numid=10, `Speaker
Playback Switch` numid=4), yet the speaker LED is not exposed as
controllable.
### `dmesg | grep -i "hda\|realtek"`
```
[ 5.133044] sof-audio-pci-intel-mtl 0000:00:1f.3: hda codecs found, mask 5
[ 5.133049] sof-audio-pci-intel-mtl 0000:00:1f.3: using HDA machine driver
skl_hda_dsp_generic now
[ 5.136112] sof-audio-pci-intel-mtl 0000:00:1f.3: Topology file:
intel/sof-ipc4-tplg/sof-hda-generic-2ch.tplg
[ 5.443198] sof-audio-pci-intel-mtl 0000:00:1f.3: loading topology:
intel/sof-ipc4-tplg/sof-hda-generic-2ch.tplg
[ 5.443529] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: Parent card not
yet available, widget card binding deferred
[ 5.458862] snd_hda_codec_alc269 ehdaudio0D0: ALC257: picked fixup for PCI
SSID 17aa:3802
[ 5.459339] snd_hda_codec_alc269 ehdaudio0D0: autoconfig for ALC257:
line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
[ 5.459344] snd_hda_codec_alc269 ehdaudio0D0: speaker_outs=0
(0x0/0x0/0x0/0x0/0x0)
[ 5.459346] snd_hda_codec_alc269 ehdaudio0D0: hp_outs=1
(0x21/0x0/0x0/0x0/0x0)
[ 5.459347] snd_hda_codec_alc269 ehdaudio0D0: mono: mono_out=0x0
[ 5.459349] snd_hda_codec_alc269 ehdaudio0D0: inputs:
[ 5.459350] snd_hda_codec_alc269 ehdaudio0D0: Mic=0x19
[ 5.497094] skl_hda_dsp_generic skl_hda_dsp_generic:
hda_dsp_hdmi_build_controls: no PCM in topology for HDMI converter 3
[ 5.512615] input: sof-hda-dsp Mic as
/devices/pci0000:00/0000:00:1f.3/skl_hda_dsp_generic/sound/card0/input17
[ 5.512685] input: sof-hda-dsp Headphone as
/devices/pci0000:00/0000:00:1f.3/skl_hda_dsp_generic/sound/card0/input18
[ 5.512737] input: sof-hda-dsp HDMI/DP,pcm=3 as
/devices/pci0000:00/0000:00:1f.3/skl_hda_dsp_generic/sound/card0/input19
[ 5.512789] input: sof-hda-dsp HDMI/DP,pcm=4 as
/devices/pci0000:00/0000:00:1f.3/skl_hda_dsp_generic/sound/card0/input20
[ 5.512838] input: sof-hda-dsp HDMI/DP,pcm=5 as
/devices/pci0000:00/0000:00:1f.3/skl_hda_dsp_generic/sound/card0/input21
```
## Expected Behavior
- The speaker mute LED should be exposed via
`/sys/class/sound/ctl-led/speaker/card0/` with `attach`/`detach`/`list` files,
**just like the microphone LED**.
- It should be automatically bound to `Master Playback Switch` (numid=10) or
`Speaker Playback Switch` (numid=4), so pressing `Fn+F1` toggles the LED
accordingly.
## Attempted Workarounds
Manual binding was attempted:
```bash
echo 10 | sudo tee /sys/class/sound/ctl-led/speaker/card0/attach
```
Result:
```
10
/sys/class/sound/ctl-led/speaker/card0/attach: No such file or directory (os
error 2)
```
The `attach` file does not exist, so manual binding is impossible.
## Analysis
The microphone LED is correctly registered and auto-bound:
- `/sys/class/sound/ctl-led/mic/card0/` contains `attach`, `detach`, `list`
- `list` returns `49` (`Dmic0 Capture Switch`)
The speaker LED is registered but **not as an audio-controllable LED**:
- `/sys/class/sound/ctl-led/speaker/card0/` contains only generic LED
attributes (`brightness`, `mode`, `power`, `uevent`)
- No `attach`, `detach`, or `list`
This strongly suggests that the ALC257 fixup for SSID `17aa:3802` (or
the SOF machine driver `skl_hda_dsp_generic`) does **not** register the
speaker LED GPIO as an audio-controllable LED via the `ctl-led`
framework.
## Requested Fix
1. Add an ALC257 fixup for Lenovo SSID `17aa:3802` that registers the speaker
mute LED with the `ctl-led` framework, similar to the microphone LED.
2. Ensure the speaker LED is auto-bound to `Master Playback Switch` or `Speaker
Playback Switch`, so `Fn+F1` toggles it.
3. If the LED GPIO is controlled through a different path in SOF, ensure
`skl_hda_dsp_generic` passes the correct LED information to `snd_hda_codec` so
`ctl-led` can create the `attach`/`detach`/`list` interface.
## Additional Notes
- `amixer` confirms `Master Playback Switch` (numid=10) and `Speaker Playback
Switch` (numid=4) exist, so the hardware control is present; the problem is
purely in LED registration/binding.
- The microphone LED case proves the kernel and driver stack can support this
on this platform, so the fix should be feasible.
- Kernel version: `7.0.0-38-generic` (Ubuntu 26.04).
---
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-38-generic 7.0.0-38.38
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: reyear 12780 F.... pipewire
reyear 12789 F.... wireplumber
/dev/snd/seq: reyear 12780 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu Oct 8 15:05:36 2026
InstallationDate: Installed on 2026-10-08 (0 days ago)
InstallationMedia: Ubuntu 26.04.1 LTS "Resolute Raccoon" - Release amd64
(20260826)
MachineType: LENOVO 21LD
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic
root=UUID=b9233851-f59a-4276-9c97-e57036055931 ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/17/2025
dmi.bios.release: 2.67
dmi.bios.vendor: LENOVO
dmi.bios.version: NJCN67WW
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: LNVNB161216
dmi.board.vendor: LENOVO
dmi.board.version: SDK0T76479 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: ThinkBook 14 G6+ IMH
dmi.ec.firmware.release: 2.67
dmi.modalias:
dmi:bvnLENOVO:bvrNJCN67WW:bd12/17/2025:br2.67:efr2.67:svnLENOVO:pn21LD:pvrThinkBook14G6+IMH:rvnLENOVO:rnLNVNB161216:rvrSDK0T76479WIN:cvnLENOVO:ct10:cvrThinkBook14G6+IMH:skuLENOVO_MT_21LD_BU_idea_FM_ThinkBook14G6+IMH:pfaThinkBook14G6+IMH:
dmi.product.family: ThinkBook 14 G6+ IMH
dmi.product.name: 21LD
dmi.product.sku: LENOVO_MT_21LD_BU_idea_FM_ThinkBook 14 G6+ IMH
dmi.product.version: ThinkBook 14 G6+ IMH
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
--
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https://bugs.launchpad.net/bugs/2169937
Title:
Bug Report: Realtek ALC257 speaker mute LED not exposed via `ctl-led`
on Lenovo (17aa:3802) with SOF driver
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