Comment 24 for bug 377741

1) Synaptics support is present:

# grep -i synapt /lib/modules/`uname -r`/build/.config
CONFIG_MOUSE_PS2_SYNAPTICS=y
CONFIG_MOUSE_SYNAPTICS_I2C=m

2) Synaptincs X.org package is present:

# dpkg -l | grep -i synap
ii xserver-xorg-input-synaptics 1.2.2-1ubuntu4 Synaptics TouchPad driver for X.Org server

3)

# dmesg | grep 8042
[ 5.700307] i8042.c: Detected active multiplexing controller, rev 1.1.
[ 5.703862] serio: i8042 KBD port at 0x60,0x64 irq 1
[ 5.703868] serio: i8042 AUX0 port at 0x60,0x64 irq 12
[ 5.703871] serio: i8042 AUX1 port at 0x60,0x64 irq 12
[ 5.703873] serio: i8042 AUX2 port at 0x60,0x64 irq 12
[ 5.703876] serio: i8042 AUX3 port at 0x60,0x64 irq 12
[ 5.726555] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input2
[ 13.354230] input: ImPS/2 Generic Wheel Mouse as /devices/platform/i8042/serio2/input/input7

For now, the workaround I use is disabling the touchpad device using XInput - I've written a script which is run during KDE session startup:

# cat disable_touchpad.sh

#!/bin/sh
xinput set-prop 'ImPS/2 Generic Wheel Mouse' 122 0