Linux for Chromebook Pixel 2015

This repository contains packages for Debian and Arch Linux that installs the Linux kernel v4.9 with a config that is somewhat optimized for the Chromebook Pixel 2015.

As of v4.9 there is no need to patch the kernel sources to get sound support.

Current kernel version: 4.9

Installation

The easiest way to get going is to install the packages if you are running Ubuntu, Debian or Arch Linux.

Ubuntu / Debian

$ git clone --depth=1 https://github.com/raphael/linux-samus
$ cd linux-samus/build/debian
$ sudo dpkg -i *.deb

Arch Linux

Install the linux-samus4 package from the AUR:

$ yaourt -S linux-samus4

Other distributions

The entire kernel patched tree is located under build/linux, compile and install using the usual instructions for installing kernels. For example:

$ git clone --depth=1 https://github.com/raphael/linux-samus
$ cd linux-samus/build/linux
$ make nconfig
$ make -j4
$ sudo make modules_install
$ sudo make install

NOTE the steps above are just the standard kernel build steps and may differ depending on your distro/setup.

Post-install steps

Once installed reboot and load the kernel.

Sound

Setup

The scripts needed to enable audio and switch between the speakers and headphones are provided in the scripts/setup/audio folder.

NOTE The scripts assume that the Broadwell driver is loaded first (index is 0). To make sure that this is the case edit the file /etc/modprobe.d/sound.conf and make sure its content includes:

options snd_soc_sst_bdw_rt5677_mach index=0
options snd-hda-intel index=1

To enable audio:

scripts/setup/audio/enable-audio.sh

amixer -c 0 cset name='DAC1 MIXL DAC1 Switch' on
amixer -c 0 cset name='DAC1 MIXR DAC1 Switch' on

To switch to speakers (note channel swapping):

scripts/setup/audio/enable-speakers.sh

amixer -c 0 cset name='Headphone Switch' off
amixer -c 0 cset name='Stereo DAC MIXL DAC1 L Switch' off
amixer -c 0 cset name='Stereo DAC MIXR DAC1 R Switch' off
amixer -c 0 cset name='Stereo DAC MIXL DAC1 R Switch' on
amixer -c 0 cset name='Stereo DAC MIXR DAC1 L Switch' on
amixer -c 0 cset name='Speaker Switch' on

To switch to headphones (note channel unswapping):

scripts/setup/audio/enable-headphones.sh

amixer -c 0 cset name='Speaker Switch' off
amixer -c 0 cset name='Stereo DAC MIXL DAC1 R Switch' off
amixer -c 0 cset name='Stereo DAC MIXR DAC1 L Switch' off
amixer -c 0 cset name='Stereo DAC MIXL DAC1 L Switch' on
amixer -c 0 cset name='Stereo DAC MIXR DAC1 R Switch' on
amixer -c 0 cset name='OUT1 Playback Switch' on
amixer -c 0 cset name='OUT2 Playback Switch' on
amixer -c 0 cset name='Headphone Switch' on

The following commands will toggle mute, decrease volume and increase volume respectively:

scripts/setup/audio/mute-toggle.sh

amixer -q -D pulse sset Master toggle

scripts/setup/audio/volume-down.sh

amixer -q -D pulse sset Master 5%-

scripts/setup/audio/volume-up.sh

amixer -q -D pulse sset Master 5%+

Users upgrading from pre-4.7 Samus kernel

To get sound working, you must unwind some of the previous samus sound settings:

1. edit the file /etc/pulse/default.pa and ensure these lines are commentted out:

#load-module module-alsa-sink device=hw:0,0
#load-module module-alsa-source device=hw:0,1
#load-module module-alsa-source device=hw:0,2

2. remove the following folders: /opt/samus and /usr/share/alsa/ucm/bdw-rt5677
3. edit the file /etc/acpi/handler.sh and remove any samus entries

NOTE: settings to toggle headphone/speaker during plug) and unplug) events still need to be implemented.

Touchpad

Since Linux 4.3 the Atmel chip needs to be reconfigured to guarantee that the touchpad works. See issue #73 for details. The linux-samus/scripts/setup/touchpad directory contains a script that does the reconfig:

$ cd linux-samus/scripts/setup/touchpad
$ ./enable-atmel.sh

This is only needed to be run once.

Keyboard

Chrome OS sets up a number of useful key mappings, such as:

• Home = Search + left arrow
• End = Search + right arrow
• PgUp = Search + up arrow
• PgDn = Search + down arrow
• Delete = Search + backspace

The keyboard.sh script will enable these mappings under standard Linux, and it will also set up mappings for special functions that do not exist on a standard 101-key PC keyboard:

• Back = Search + F1
• Forward = Search + F2
• Reload = Search + F3
• BrightnessDown = Search + F6
• BrightnessUp = Search + F7
• VolumeMute = Search + F8
• VolumeDown = Search + F9
• VolumeUp = Search + F10

i.e. the Chromebook's F-keys will produce F1-F10 without the Search modifier, and perform the marked functions with the Search modifier. F1-F3 can be handled by apps (such as a web browser) while F6-F10 tend to be handled by the desktop environment. The latter keys were tested with Xfce.

This will add a command to ~/.xsessionrc that enables the mappings on login:

$ cd linux-samus/scripts/setup/keyboard
$ ./keyboard.sh

Xorg

To enable X11 acceleration run the xaccel.sh script:

$ cd linux-samus/scripts/setup/xorg
$ ./xaccel.sh

Brightness

The script scripts/setup/brightness/brightness can be used to control the brightness level.

$ cd scripts/setup/brightness
$ ./brightness --help
Increase or decrease screen brightness
Usage: brightness --increase | --decrease

Put scripts/setup/brightness in your path and bind the F6 key to brightness --decrease and the F7 key to brightness --increase for an almost native experience.

Similarly the script script/setup/brightness/keyboard_led can be used to control the keyboard backlight, bind the ALT-F6 key to keyboard_led --decrease and ALT-F7 to keyboard_led --increase.

Both these scripts require write access to files living under /sys which get mounted read-only for non-root users on boot by default. If your system uses systemd (e.g. ArchLinux) then the file script/setup/brightness/enable-brightness.service contains the definition for a systemd service that makes the files above writable to non-root user. Run systemctl enable enable-brightness.service for the service to run on boot.

systemd

./setup.systemd.sh

The same directory also contains setup.systemd.sh. When executed, it copies scripts to /usr/local/bin and configures systemd to run the script enable-brightness.sh on boot.

OpenRC

./setup.openrc.sh

The same directory also contains setup.openrc.sh. When executed, it copies scripts to /usr/local/bin and configures OpenRC to run the script enable-brightness.sh on boot using the local service.

Contributions

This repo exists so that we can all benefit from one another's work. Thomas Sowell's linux-samus repo was both an inspiration and help in building it. The hope is that others (you) will also feel inspired and contribute back. PRs are encouraged!