When I booted up my newly installed Ubuntu 11.04, I discovered, to my dismay, that the backlight was off by default. The keyboard shortcut (which is Fn+F6 on my Acer Aspire 4736) for turning on the backlight doesn't seem to work. I have been trying to resolve this problem for the past 2 days now, but with no success. By the way, the backlight did work properly once or twice at random - but the problem again popped up as soon as I restarted my system.