I’ve recently updated Ubuntu on my Subnotebook to version 11.10. After the update, my touchpad did not work anymore.

To fix this, first open /etc/default/grub with your favourite editor.

sudo vim /etc/default/grub

Find the line

GRUB_CMDLINE_LINUX=""

and change it to

GRUB_CMDLINE_LINUX="i8042.nopnp"

Now update grub and reboot.

sudo update-grub

sudo shutdown -r now