I'm using an old IBM Thinkpad X21 laptop with Debian Squeeze as a server (irc bouncer etc.). I'd like to turn the display backlight off to save power and the backlight CCFLs itself but I haven't found a way to do so.

The screen goes blank automatically after some time but the backlight still stays on.

DPMS via xset does not work because X is not installed.

Fn+F3 should turn the LCD off but it doesn't work either. I think I saw some bug reports for thinkpad-acpi about this problem.

Is there a way to do it at all? Or do I just have to keep it on, brightness at minimum?

You can try it with the setterm command.should do the job, but you may want to have a look at to get more info about the other options.

I tried to use setterm -powersave powerdown and setterm -powerdown 5 (for 5 minute timeout) but neither of them worked... Could the BIOS setting "Screen blanking" (enabled/disabled) affect this? Changing that setting didn't do anything but I hadn't tested setterm commands back then.

Thinkpads used to have a hot key to turn off backlight. I think it was alt and two n keys or something like that.

Fn + F3 should do it but it didn't work. What do you mean by two n keys? Tapping "n" key twice?