I thought I'd take some time to document some Chromebook trackpad tweaks that could be useful on Arch Linux in particular. Note that I'm running this natively rather from crouton.

• Using the Chromium OS Trackpad Driver on Linux
  • Installation
  • Configuration
• Enable Natural Scrolling, aka "Australian Scrolling"

Using the Chromium OS Trackpad Driver on Linux

While the Synaptics driver works decently with the Acer C720 chromebook, I've that xf86-input-cmt, the Linux port of the Chromium OS Trackpad driver more preferable because its behavior is much more similar to what's on Chrome OS (since, Chromium OS driver and all).

Installation

xf86-input-cmt depends on these packages in the AUR which you'll need to install first:

• libevdevc
• libgestures
• xf86-input-cmt-setup

Configuration

Copy one of the configs here that corresponds to the Chromebook model you use and save it under /etc/X11/xorg.conf.d/ (eg. peppy). If you're not sure what that is, go here, look for your Chromebook model and check the Board Name.

For me, the model is the Acer C720, which corresponds to the peppy board name, so I copied this into /etc/X11/xorg.conf.d as 50-trackpad-cmt-peppy.conf.

Restart the X server, then, you should be good to go!.

Enable Natural Scrolling, aka "Australian Scrolling"

I've gotten used to "Natural Scrolling", which is called "Australian Scrolling" in Chrome OS. To enable it, use xorg-xinput, which can also be used to configure the other options.

First, determine the id of the trackpad.

xinput

This outputs something like this:

⎡ Virtual core pointer                    	id=2	[master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer              	id=4	[slave  pointer  (2)]
⎜   ↳ Cypress APA Trackpad (cyapa)            	id=12	[slave  pointer  (2)]
⎣ Virtual core keyboard                   	id=3	[master keyboard (2)]
    ↳ Virtual core XTEST keyboard             	id=5	[slave  keyboard (3)]
    ↳ Power Button                            	id=6	[slave  keyboard (3)]
    ↳ Video Bus                               	id=7	[slave  keyboard (3)]
    ↳ Power Button                            	id=8	[slave  keyboard (3)]
    ↳ Sleep Button                            	id=9	[slave  keyboard (3)]
    ↳ Sleep Button                            	id=10	[slave  keyboard (3)]
    ↳ HD WebCam                               	id=11	[slave  keyboard (3)]
    ↳ AT Translated Set 2 keyboard            	id=13	[slave  keyboard (3)]

The corresponding entry here is Cypress APA Trackpad, so the id you need to pass is 12.

Then, determine what the property number corresponds to Australian Scrolling:

xinput --list-props 12|grep 'Australian Scrolling'

This outputs:

           Australian Scrolling (448): 0

The number in the parentheses is the property ID you need to modify.

To enable "Australian Scrolling", simply run set-prop with the id of the trackpad, the ID of the property, and then 1:

xinput --set-prop 12 448 1

This will immediately enable natural scrolling.