While playing with my xorg.conf file I accidentally turned off the scrolling area of my trackpad. Normally, if you put your finger at the right hand side of the trackpad, you can scroll up and down. If you put your finger at the bottom of the pad, you can scroll left or right.
In figuring out how to resolve the issue I discovered something deeply awesome. Circular scrolling. Now, starting from any side of the pad, I can move my finger clockwise round the trackpad to scroll down, anti-clockwise to scroll up. Just like the iPod. It’s outstanding on long documents where even a scroll wheel becomes tiring.
Gotta love linux baby!
For the techies, here’s the relevant section of my xorg.conf (see man synaptics for more info):
Identifier "Synaptics Touchpad"
Option "SendCoreEvents" "true"
Option "Device" "/dev/input/mice"
Option "Protocol" "auto-dev"
Option "CircularScrolling" "1"
Option "Emulate3Buttons" "true"
Option "SHMConfig" "true"
I also discovered another great application synclient which allows you to change the touchpad settings on the fly. It also allows you to monitor touchpad input with the -m flag. It’s great to test your settings and figure out what works before committing the changes to xorg.conf.
Update at 4 May 2010: On Ubuntu 9.04 and later this is no longer relevant. Instead enable SHMConfig through hal, see this for more info, and then install gsynaptic.