screen brightness stuck on high

For a long time, when I wake up my laptop, some of the time the screen brightness is stuck on max.  Fn-F10/F11 to lower/raise brightness do nothing.  If I put laptop to sleep and wake up again, same thing.  The only solution is to reboot.  Annoying!

It doesn't always happen, I can't figure out a pattern, but when it does the only answer is to reboot.

Thoughts?

Thanks.