Comment 14 for bug 129477

This is an alps pad rather than a synaptics one - nevertheless, the issue is that the kernel doesn't recognise the latest generation alps pads. Relevant code is drivers/input/mouse/alps.c (which gets built into the psmouse module). Since it's not being recognised it's falling back to ps/2 emulation mode, which gives you relative motion but nothing else. It's likely to be a simple fix.