Comment 2 for bug 129477

The same problem occurs on the new Dell Inspiron 1720.

The trackpad in this case is an ALPS GlidePoint (according to Windows).

Even with the most recent production kernel (2.6.22) this device is
not recognized and defaults to a generic PS/2 mouse:

cat /proc/bus/input/devices

   I: Bus=0011 Vendor=0002 Product=0001 Version=0000
   N: Name="PS/2 Generic Mouse"
   P: Phys=isa0060/serio1/input0
   S: Sysfs=/class/input/input1
   U: Uniq=
   H: Handlers=mouse0 event1 ts0
   B: EV=7
   B: KEY=70000 0 0 0 0 0 0 0 0
   B: REL=3

It appears that this device is returning something that the macro:

  SYN_ID_IS_SYNAPTICS

defined in the kernel source file:

  drivers/input/mouse/synaptics.h

does not recognize as being a synaptics compatible device, or if
it does then the subsequent trackpad model ID or capabilities tests
fails. In my case at least, I don't think this is a problem in

  xserver-xorg-input-synaptics (Ubuntu)

but rather an issue for the synaptics driver maintainers.