[BUG] Internal speakers silent on Dell 16 Plus (DB16250) despite fully working driver/mixer chain

[EdNoepel]

Possibly duplicate of two other Lunar Lake bugs reported for Lenovo laptops, but did not want to derail the conversation there.

Bug Report: Internal speakers silent on Dell 16 Plus (DB16250) despite fully working driver/mixer chain

Summary

On a Dell 16 Plus (DB16250, Intel Lunar Lake), the internal speakers produce no audio output. This is NOT a detection or mute issue — the SOF driver loads correctly, the RT722 SoundWire topology initializes without errors, every relevant ALSA mixer control is unmuted and at a normal level, and PipeWire correctly routes an active stream to the Speaker sink. Writing audio directly to the hardware PCM device (bypassing PipeWire entirely) still produces silence. This points to a firmware/kernel-level failure to actually enable the physical amplifier output, despite the driver reporting success at every stage.

System information

• Machine: Dell 16 Plus, model DB16250
• CPU/Platform: Intel Lunar Lake
• OS: Ubuntu 26
• Kernel: 7.0.0
• Audio codec: Realtek RT722 (SoundWire)
• SOF firmware: ADSPFW 2.14.1.1 (booted successfully)
• Topology loaded: intel/sof-ipc4-tplg/sof-lnl-rt722-l0.tplg (ABI 3:29:1, Kernel ABI 3:23:1)
• Sound card: sof-soundwire / DellInc.-Dell16PlusDB16250-07V73W

Steps to reproduce

1. Fresh install of Ubuntu 26, kernel 7.0.0, on a Dell 16 Plus DB16250.
2. Boot the system; audio hardware is detected without errors.
3. Attempt to play any audio (system sounds, media, etc.) through the internal speakers.
4. No sound is produced, despite no errors being reported anywhere in the stack.

Expected behavior

Audio played through the default Speaker sink should be audible through the internal speakers.

Actual behavior

Complete silence, with no errors surfaced at the kernel, ALSA, or PipeWire/WirePlumber level.

Diagnostic steps already performed (ruling out common causes)

1. Kernel driver loads and initializes cleanly

dmesg | grep -i -E "sof|soundwire|snd"

Relevant output:

sof-audio-pci-intel-lnl 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if 0x040380
sof-audio-pci-intel-lnl 0000:00:1f.3: hda codecs found, mask 4
sof-audio-pci-intel-lnl 0000:00:1f.3: Firmware file: intel/sof-ipc4/lnl/sof-lnl.ri
sof-audio-pci-intel-lnl 0000:00:1f.3: Loaded firmware library: ADSPFW, version: 2.14.1.1
sof-audio-pci-intel-lnl 0000:00:1f.3: Booted firmware version: 2.14.1.1
sof-audio-pci-intel-lnl 0000:00:1f.3: loading topology: intel/sof-ipc4-tplg/sof-lnl-rt722-l0.tplg
sof-audio-pci-intel-lnl 0000:00:1f.3: Topology: ABI 3:29:1 Kernel ABI 3:23:1
sof_sdw sof_sdw: ASoC: Parent card not yet available, widget card binding deferred

No errors. Firmware boots and topology loads successfully.

2. ALSA sees the Speaker PCM device

aplay -l

card 0: sofsoundwire [sof-soundwire], device 2: Speaker (*) []

3. Every relevant mixer control is unmuted and at normal levels

amixer -c 0 contents

Key controls, all correctly enabled:

• Speaker Switch: on
• Pre Mixer Speaker Playback Volume: 45/45 (max, unmuted; dBscale-min=-90dB, step=2dB)
• Post Mixer Speaker Playback Volume: 45/45 (max, unmuted)
• Post Mixer Speaker Playback DRC switch: on
• rt722 FU06 Playback Volume: 67/87 (normal operating level, not muted)

No control anywhere in the chain is muted or at zero.

4. PipeWire correctly routes to the Speaker sink

wpctl status

Sinks:
*   61. Lunar Lake-M HD Audio Controller Speaker [vol: 0.68]
Streams:
   106. speech-dispatcher-dummy
        109. output_FL > Speaker:playback_FL [init]
        110. output_FR > Speaker:playback_FR [init]

Speaker is the default sink, unmuted, with an active stream correctly routed to it.

5. Hardware-level test bypassing PipeWire entirely

speaker-test -D hw:0,2 -c 2 -t wav

Result: confirmed silence, even writing directly to the hardware PCM device with no audio server involved.

Conclusion

Every layer of the stack — kernel driver, firmware boot, topology load, ALSA mixer state, and PipeWire routing — reports success and shows a fully open, unmuted signal path. Yet no audio is physically produced, even when bypassing the desktop audio stack entirely. This strongly suggests the SOF firmware/topology for this board is not actually enabling the physical speaker amplifier output, despite reporting a successful playback stream. This may be a missing board-specific quirk or amp-enable sequence for the Dell 16 Plus DB16250 in the SOF topology or ASoC machine driver.