I recently switched from Slackware 13.37 to Arch Linux on my Eee PC 900HA and everything worked well except for the touchpad. The cursor sometimes would randomly jump around and performing a middle click using a two-finger tap was very difficult because if both fingers didn’t touch at exactly the same time, it would get detected as a two-finger scroll.
I had xf86-input-synaptics installed, so I tried changing all kinds of options in /etc/X11/xorg.conf.d/10-synaptics.conf, but nothing seemed to make the touchpad work like before.
After searching around a while and looking around in my logs, I found that in Slackware 13.37, the touchpad was recognized as an “ImPS/2 Logitech Wheel Mouse”, whereas in Arch Linux, it was recognized as an “ETPS/2 Elantech Touchpad”.
In order to make Arch Linux detect my touchpad as a mouse instead of a touchpad I had to change a parameter in the psmouse module to get it to probe the correct protocol extension, or something.
To get information about the psmouse module:
modinfo psmouse
To change the parameter, remove the module then add the module again with the new parameter:
rmmod psmouse
modprobe psmouse proto=imps
Now my touchpad is detected as a “ImPS/2 Generic Wheel Mouse” and everything works well like before.
To make this change permanent:
Add options psmouse proto=imps to /etc/modprobe.d/psmouse.conf
Source