After selecting the OS to load with grub, 12.04 boots to a dark screen. It seems a minor problem, because I only have to press the brightening key on may keyboard to cast some light. But every single time I reboot, the dark screen returns. is there a workaround for this?
This is a known bug. If you have a Launchpad account, mark it as affecting you to increase its heat, and thereby its likelihood of attracting developer interest.
In the meantime, a possible workaround might be to use a display manager other than LightDM, since the bug appears to have appeared at the same time as LightDM became the default.
To instead use GNOME Display Manager (which used to be the default), run
To restore LightDM, run