Comment 9 for bug 63051

As I recall the newest version of Ubuntu (FEISTY) still has issues with the trident driver flaking out and blowing stuff up. The solution I came up with is to get the DEBIAN Trident driver. You can get it from the DEBIAN repos. I copied the driver file over the Ubuntu driver, then modified my xorg.conf file to have

Section "Device"
        Identifier "Generic Video Card"
        Driver "trident"
        Option "Accelmethod" "xaa" <----This is the change
        BusID "PCI:1:0:0"
EndSection

I've found that whenever the video brightness changes, such as when the power state changes, or when I open the lid, the screen seems to expand the upper left 1/4 of the screen to cover the whole screen. A simple ctrl-alt-F3, ctrl-alt-F7 tends to fix it, though I have found that if you switch to text mode BEFORE you login on initial startup then the screen can sometimes just turn blue and become unresponsive. The work-around being you login BEFORE the text mode->gui mode switch, and give it about 10 seconds for everything to settle before you attempt it.

YMMV