Touchpad scroll not working after installing gdm on ThinkPad E530

Touchpad scroll not working after installing gdm on ThinkPad E530

I have gone through
http://askubuntu.com/questions/224628/touchpad-not-detected-on-thinkpad-e530,
but no use.
When I installed Ubuntu 12.04, my touchpad was working fine with
scrolling. When I installed 'gdm' it stopped working. Then, I switched
back to 'lightdm', but problem is still there.
$ xinput
⎡ Virtual core pointer id=2 [master pointer
(3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave
pointer (2)]
⎜ ↳ Logitech USB Optical Mouse id=13 [slave
pointer (2)]
⎜ ↳ PS/2 Synaptics TouchPad id=11 [slave
pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard
(2)]
↳ Virtual core XTEST keyboard id=5 [slave
keyboard (3)]
↳ Power Button id=6 [slave
keyboard (3)]
↳ Video Bus id=7 [slave
keyboard (3)]
↳ Power Button id=8 [slave
keyboard (3)]
↳ Integrated Camera id=9 [slave
keyboard (3)]
↳ AT Translated Set 2 keyboard id=10 [slave
keyboard (3)]
↳ ThinkPad Extra Buttons id=12 [slave
keyboard (3)]