why is it that sometimes i can't manually control lcd brightness?

unless i reboot my x200, i can't change my LCD brightness... not with the FN+ Home/End keys, nor changing the Power Plan in thinkvantage power manager. i know the plans are changing because i can heat my cpu fan spin down and watch my cpu speed drop in cpu-z, but the LCD brightness does not change.

it also does not change if i pull out the ac adapter and plug it back in (with battery in). it is supposed to; thats how it is set in my power plan

 

did you try closing the lid and trying again? it happen to me once and i closed the lid and opened it again and it worked.

 

It happens on occasion for me as well. It seems like a wake up issue, cuz it only happens after sleep/hibernation in my case. It's never happened on a cold boot. I've tried to see if it's the number of times I've put it to sleep, to see if it's caused by an incrementation of sleep cycles, but it seems pretty random. I've had it as few as after the first sleep/wake-up, and sometimes I lose brightness control after as many as ten or more.

What's the deal with it? I've no clue. Along with the fingerprint reader being on the fritz occasionally. It's gradually wearing away at my appreciation for this laptop.