So,in may laptop with Ubuntu 12.04, the startup is like this:
1) I see the Ubuntu logo with the 5 dots on a purple background for a few seconds.
2) The screen goes completely black (no back light), but it's not shut down, i can still see shadows.
3) The system is fully loaded (i can log-in), but the screen is still shadowy (no back light).
4) I have to wait about 1 minute (logged or not) for the back light to turn on.
How do I prevent the system from shutting the back light at startup ?