CS4208 audio driver for the 12-inch MacBook

Out-of-tree audio driver for the Cirrus Logic CS4208 codec in the 12-inch MacBook (MacBook9,1 / 2016 and MacBook10,1 / 2017).

The mainline kernel has no working configuration for this codec on these machines: the codec is detected, but the speaker amplifier is never enabled, so the built-in speakers stay silent. This module replays the initialization the codec needs (reverse-engineered from macOS) and adds proper headphone/speaker routing on top.

Based on davidjo's snd_hda_macbookpro and forked from leifliddy's macbook12-audio-driver.

What works

• Internal speakers
• Headphone jack
• Automatic speaker / headphone switching on plug / unplug
• Volume control — needs one extra config step, see Speaker volume
• Internal microphone

Supported hardware & kernels

Models	MacBook9,1 (2016), MacBook10,1 (2017)
Not supported	MacBook8,1 (2015)
Kernels	≥ 5.0 (including the 6.17+ sound/hda/codecs layout)
Audio server	PipeWire or PulseAudio

Installation

1. Install build prerequisites

Ubuntu / elementary / Debian

sudo apt install dkms gcc make git wget linux-headers-$(uname -r)

Fedora

sudo dnf install dkms gcc make git wget kernel-devel

Arch

sudo pacman -S dkms gcc make git wget linux-headers

2. Build & install the module (DKMS — recommended)

DKMS rebuilds the module automatically whenever you install a new kernel, so audio keeps working across kernel updates.

git clone https://github.com/breitburg/macbook12-audio-driver.git
cd macbook12-audio-driver
sudo ./install.cirrus.driver.sh -i
sudo reboot

Note

The build downloads the matching kernel source tarball to obtain the HD-audio codec headers, so an internet connection is required at build time — including when DKMS rebuilds after a kernel update.

Important

Keep the cloned directory in place. The DKMS install links to it, and removing it will break the automatic rebuild on the next kernel update.

To uninstall:

sudo ./install.cirrus.driver.sh -u

Manual build (fallback — does not survive kernel updates)

git clone https://github.com/breitburg/macbook12-audio-driver.git
cd macbook12-audio-driver
sudo ./install.cirrus.driver.sh
sudo reboot

3. Speaker volume (required)

The internal speaker has no usable hardware volume control — the codec's only analog amplifier is wired to the headphone path. PipeWire therefore has to apply volume in software for this card. Without this step the volume slider appears to do nothing on the speakers.

Check your WirePlumber version first:

wireplumber --version

WirePlumber 0.5+ (most current distros) — create /etc/wireplumber/wireplumber.conf.d/51-macbook-cs4208-softvol.conf:

monitor.alsa.rules = [
  {
    matches = [ { device.name = "alsa_card.pci-0000_00_1f.3" } ]
    actions = { update-props = { api.alsa.soft-mixer = true } }
  }
]

WirePlumber 0.4 — create /etc/wireplumber/main.lua.d/51-macbook-cs4208-softvol.lua:

table.insert(alsa_monitor.rules, {
  matches = {
    { { "device.name", "equals", "alsa_card.pci-0000_00_1f.3" } },
  },
  apply_properties = {
    ["api.alsa.soft-mixer"] = true,
  },
})

Copy-paste-ready versions of both live in contrib/wireplumber/.

Then pin the hardware amps to full, persist them, and restart WirePlumber:

amixer -c0 sset Master 100% unmute
sudo alsactl store
systemctl --user restart wireplumber

Note

On these MacBooks the audio controller is at PCI 00:1f.3, which is what the config matches. If yours differs, find the card name with wpctl status or pactl list cards short.

Verifying

# confirm this module (not the in-tree stub) is loaded:
modinfo snd_hda_codec_cs420x | grep filename     # should point at .../updates/...

# then play a test sound and plug/unplug headphones — audio should follow:
wpctl status

How it works & limitations

The CS4208 in these MacBooks drives the speakers over a digital link (converter 0x0a → pin 0x1d, with the amplifier enabled by a GPIO) and the headphones over the analog DAC (converter 0x02 → pin 0x10). The module replays the macOS init for both paths and, on a jack interrupt, re-points the active stream onto the correct converter (disabling the speaker pin so it doesn't bleed while headphones are in).

• Switching is done at the codec level and cooperates with PipeWire's own jack handling.
• Because the speaker relies on software volume, very low headphone levels can sound slightly compressed (reduced effective bit depth). Normal listening levels are unaffected.

Credits

• davidjo — original snd_hda_macbookpro reverse-engineering this is built on
• leifliddy — macbook12-audio-driver, the base for this fork