I recently installed the latest drivers and my screen backlight turned off. The problem is that my Fn-F7 key combination doesn't work, so I can't turn it back on. I can see my screen at night if I hold a source of light next to the screen. So I can still do some trivial things with my laptop. Is there a way to turn the backlight on without using Fn-F7 key combination, either via the command line, or some other way?