I'm running ubuntu 11.10 and I installed the Ati driver from the oficial page. When i reboot, the grub and the splash screen are working (at lower resolution) but instead of the login screen, it shows "input not supported" message. If I use "Ctrl+Alt+ keypad +" I can see my login screen at 640x480 resolution and login.
I don't know how to make login screen displays 1440x900@60, that is the resolution set on my session.
I'm running Ubuntu 11.10 with ati hd4200 video card, a monitor acer aL1916w that supports the resolution 1440x900.