My employer recently provided a MacBook Pro 17" sweet machine! One of its great features is keyboard illumination. It really rocks in low lit areas or late at night while in bed. However after reinstalling Snow Leopard I ran into an issue or at least what I thought was an issue.
When I first got the laptop keyboard illuminated at all times and F6/F7 keyboard brightness function keys always allowed adjustments. After Snow Leopard reinstall keyboard illumination was no longer functioning and pressing F6/F7 did nothing; in fact on screen graphic showed a circle with diagonal line. I assumed I was missing a driver or something went wrong during reinstall process.
Immediately I googled the problem and found a few posts with similar issue however everyone posted "its working now and I don't know what I did to make it work" ~not very helpful!
So I thought I would post my experience in case others are pulling hair trying to figure it out.
It seems to me Apple has changed keyboard illumination functionality. Instead of always illuminating the keyboard and allowing F6/F7 adjustments at all times. NOW! and here is the important part you must be in a dark room before keyboard will illuminate AND allow any F6/F7 brightness adjustments. How I
Uncovering both speakers auto brightened my screen, keyboard no longer illuminated and I could no longer adjust keyboard brightness using F6/F7 function keys.
If you really think about it that really makes sense because why would you need your keyboard lit when in a bright sunny setting. Simply a battery drain. I just wish this change in functionality was posted somewhere on Apple's site. If it was I missed it or could not find it. (I looked)
Hope this helps.