I upgraded my Acer laptop to Ubuntu 3.8.0-0.2-generic from the Raring repositories today. I get a blank screen when I boot up with no text or gui. I can tell that the system is starting correctly and I can access the machine via ssh. I can get the screen to work if I add 'nomodeset' in /etc/default/grub. However, doing so prevents me from changing screen brightness from the maximum value. I tried using 'ubuntu-bug linux-image-3.8.0-0-generic' to submit a bug report, but it is complaining that it is a mainline kernel. Can someone point me in the right direction to report this bug? This is a regression from the previous 3.7 kernel.