void-installer/docs/KERNEL7_AUDIO_XPS9700.md

Kernel 7 Audio Troubleshooting for Dell XPS 17 9700

Symptom

On the Niri live ISO booting kernel 7, audio shows only HDMI devices and "Dummy Output" in wpctl status. Internal speakers and headphone jack do not appear.

Root Cause

The XPS 17 9700 is a Dell SoundWire platform requiring SOF + SoundWire for internal audio on modern Linux kernels. The issue is not PipeWire misconfiguration. Common causes are:

1. Kernel driver stack selection issue (wrong path selected at boot)
2. Missing or mismatched SOF firmware/topology
3. Missing or mismatched sof-soundwire UCM profiles
4. A kernel SoundWire regression

Diagnostic Steps

1. Verify the driver stack is loading

Boot into the live ISO and check which driver is active:

# Should show SOF driver for internal audio
lsmod | grep -E '^sof|^snd_sof'

# Should show the SoundWire machine driver
lsmod | grep -E 'sof_sdw|sof.*mach'

# Check kernel logs for SoundWire errors
sudo dmesg | grep -Ei 'soundwire|sdw|sof.*error|topology.*-22'

2. Test explicit SOF driver selection

If internal audio is missing, the kernel's auto-detection may have selected the wrong path. At the GRUB/boot menu, edit the kernel command line and add:

snd-intel-dspcfg.dsp_driver=3

This explicitly forces SOF (value 3) for the audio stack. Options are:

• 0: auto (kernel's default)
• 1: legacy HDA
• 3: SOF (correct for this laptop)
• 4: AVS

Then boot and re-check:

wpctl status

3. Verify package completeness

Ensure the live image has the required audio support packages:

xbps-query -l | grep -E '^ii.*sof-firmware|alsa-ucm-conf|alsa-utils'

Expected output should include:

• sof-firmware (Sound Open Firmware binaries and topology)
• alsa-ucm-conf (Use Case Manager profiles for sof-soundwire)
• alsa-utils (ALSA utilities and initial mixer state)

4. Check PipeWire/WirePlumber state

Once the kernel exposes the internal audio devices (they should appear in wpctl status), verify PipeWire is reading them correctly:

# List all devices seen by PipeWire
pw-cli ls Device

# Check WirePlumber's ALSA monitor for errors
journalctl -u wireplumber.service -n 50

# Manually re-scan if needed
pw-cli list-objects Module | grep monitor

If It Still Fails

Check for a kernel regression

Recent kernel versions 6.9 and 6.10 had SoundWire regressions affecting XPS-series Dell laptops. These were fixed in:

• 6.9.x (fixed in 6.9 stable releases)
• 6.10.11+

If kernel 7.x shows the same symptoms, check the SOF upstream issues for similar reports.

Compare against a known-good kernel

If kernel 7 still fails with dsp_driver=3:

1. Boot with the fallback kernel 6 (available in the Niri live ISO GRUB menu)
2. Test audio on kernel 6
3. If audio works on kernel 6 but not kernel 7, there is likely a kernel-7-specific regression

Report findings to:

• SOF upstream
• Void Linux

Manual ALSA routing (for microphone issues)

If speakers work but the internal microphone does not, manually set the mic input mux:

amixer --card 1 set 'rt715 ADC 24 Mux' 'DMIC3'

Then persist the state:

sudo alsactl store

References

• ArchWiki: Dell XPS 17 (9700)
• ArchWiki: Sound Open Firmware
• SOF upstream issue 4999: 6.8.9→6.9.0 regression
• Kernel docs: intel-dsp-config
• XPS 9700 Ubuntu fix guide

Live ISO Packages

The mainline-niri Niri live ISO includes:

• sof-firmware: Intel SOF binary and topology files
• alsa-ucm-conf: ALSA Use Case Manager profiles, including sof-soundwire
• pipewire and wireplumber: Session and policy management
• linux-mainline: Kernel 7.x with SOF support
• linux: Kernel 6.x fallback entry in GRUB

The build ensures both kernels are available to test audio driver behavior across kernel versions.