Using Ubuntu as main OS for years now on all Laptop and desk
top at home, I am regularly in front of common problems. But one of the most anoying is the « backlight off bug »,
So only one way to restore it:
sudo vbetools dpms on
This is the only solution I have found to restore the « ON » state.
After any reboot, the LCD stay ON.
Ubuntu is sometimes frustrating for newbies. So here is ONE solution.
Have Fun(buntu ?)