I have a fairly basic Advent keyboard with backlit keys. The colour of the backlight is controlled with a special modifier key on the keyboard + F1/2/3/4.
Since around the time of updating to Windows 8.1 and updating to UEFI BIOS on my GA-Z68X-3BH, these brightness controls don't work unless I unplug the USB connector and plug it back in (a nuisance). I've recently realised that they also work outside of Windows, with the backlight level then remaining fixed at whatever level I set it at (including after sleeping).
FWIW I've tried SharpKeys, which doesn't even notice when I press the light modifier key (or subsequent modified Fx keys).
Any help much appreciated... I won't be at all surprised if I add to my collection of tumbleweed badges with this question...