chell_audio

Guide to working Linux audio on Chromebook hardware CAROLINE, CHELL, SENTRY. Tested on Arch Linux 5.8 kernel and Debian Buster.

Requirements

• You need the kernel module snd_soc_skl available and loaded. You can check with lsmod | grep snd_soc_skl. This commonly is already built into your kernel; on Ubuntu, try installing linux-modules-extra, otherwise you will need to build it from source using the configuration item CONFIG_SND_SOC_INTEL_SKYLAKE
• Some have reported issues with intel_iommu using this firmware, if you don't need it disable it in your bootloader.
• Clone this repo: git clone --recurse-submodules https://github.com/iofq/chell_audio
• Optional but recommended: package acpid for auto-detecting headphone plug events.
  • Installed by default on Ubuntu 12.04+.
  • On Arch, pacman -S acpid && systemctl enable --now acpid

Steps:

If you cloned this repository without --recurse-submodules

git submodule init && git submodule update

Copy the contents of the galliumos-skylake/lib/firmware directory into /lib/firmware:

sudo cp galliumos-skylake/lib/firmware/* /lib/firmware

Copy the contents of the firmware directory into /lib/firmware.

sudo cp firmware/intel/* /lib/firmware/intel/

Copy the contents of the ucm2 directory into /usr/share/alsa/ucm2:

sudo cp -r ucm2/* /usr/share/alsa/ucm2

Copy the contents of the galliumos-skylake/etc directory into /etc:

sudo cp -r galliumos-skylake/etc/* /etc

At this point, after a reboot you should have working audio! Volume can be set with amixer set Master 50% unmute and headphone<->speaker detection should work.

Sources:

This github issue is the main source of all work done on this issue. If this guide didn't work, start here. Mad props to everyone over at GalliumOS.

Also thank you to metaquanta for pointing me towards the correct resources.