Comment 37 for bug 775950

I have a Lenovo 460 with Ubuntu 11.04 on the machine. I am having similar issues where I am unable to boot into the new kernel, unless I am plugged in to the AC power adapter I have no issues booting into the OS. I have installed the latest graphics driver from AMD for my ATI switchable graphics.. Following this line-up to get the driver to properly install I had to Install the prerequisite packages:

$ sudo apt-get install build-essential cdbs fakeroot dh-make debhelper debconf libstdc++6 dkms libqtgui4 wget execstack libelfg0 dh-modaliases

If you are using the x86_64 architecture (64 bit), be sure to install "ia32-libs" on your machine, if you do not it will not function

$ sudo apt-get install ia32-libs

Download the latest Catalyst package.

This package contains both the 32-bit and 64-bit driver. Current Version is 11.6

$ cd ~/; mkdir catalyst11.6; cd catalyst11.6/
$ wget http://www2.ati.com/drivers/linux/ati-driver-installer-11-6-x86.x86_64.run
$ chmod +x ati-driver-installer-11-6-x86.x86_64.run

Create .deb packages.

$ sudo sh ./ati-driver-installer-11-6-x86.x86_64.run --buildpkg Ubuntu/natty

Install .debs.

$ sudo dpkg -i fglrx*.deb

Generate a new /etc/X11/xorg.conf file

Create the ATI version of the Xorg.conf file.
This is a Generic Configuration... This works great for my machine which is a Lenovo Y460

$ sudo aticonfig --initial -f

After just reboot your machine

After following this proceedure I am still unable to start Ubuntu without having to be plugged into the wall... I hope the fix will come soon...