Touchpad not working after upgrading to Ubuntu Intrepid

If you find that your laptop touchpad is not working after upgrading to Ubuntu 8.10 Intrepid, it may be that your SHMConfig is not enabled.  The official instructions are to open a terminal and enter the following command:

gksudo gedit /etc/hal/fdi/policy/shmconfig.fdi

Then put this into the file (which was empty in my case):

<?xml version="1.0" encoding="ISO-8859-1"?>
<deviceinfo version="0.2">
 <device>
  <match key="input.x11_driver" string="synaptics">
   <merge key="input.x11_options.SHMConfig" type="string">True</merge>
  </match>
 </device>
</deviceinfo>

After a reboot, your touchpad is hopefully working again. Also, you should have a Touchpad entry in the System menu: System -> Preferences -> Touchpad