I use Linux on my laptop, and whenever a game switches into fullscreen mode, the backlight goes off on my screen. Does anyone know either:
a) a general fix for this
or
b) a specific fix for DOSbox?

Thanks!

I found a post on another forum where user Jelaku says:

"Apparently if my monitor's brightness is at 0, and I enter or exit a full screen game, it has a chance to randomly do it. (meaning turn off the backlight). Putting it back to a higher value than 0 has fixed the issue, I just never really tied the two together."

You may also try turning off dynamic contrast if it's on. I had problems with my monitor until I did that.

Maybe this can help you:
Ubuntu forums