Shevin

one of the features that ubuntu 12.04 promised was better support for dual-monitor however after I upgraded from ubuntu 11.10  to ubuntu 12.04 I noticed if I change the display settings it will freeze for example I noticed:

- I  move the external monitor to the left of laptop monitor , (or above it) it freezes
- I try to turn of the laptop monitor ,so I only have my external monitor it will freeze again. the mouse and keyboard stop responding and the only way key that respond is
 ALT+PRINTSCREEN+K (to restart the X server)

I openned a bug in Launchpad and I tried every possible solution  after pulling my hair and not sleeping in the whole night .Here is how I fixed it : To fix dual monitor freeze in ubuntu 12.04 you need to install the older version of  xserver-xorg-input-evdev

1- Download the following two packages to your desktop:

- xserver-xorg-input-evdev-udeb_2.6.99.901-1ubuntu3~lp921236_amd64.udeb (24.0 KiB)

- xserver-xorg-input-evdev_2.6.99.901-1ubuntu3~lp921236_amd64.deb (38.0 KiB)

2- Open a terminal

cd Desktop

sudo dpkg -i *.deb

3- Restart your computer or if you are lazy just restart the X Server (ALT+PRINTSCREEN +K)