Brightness gets stuck when resume from sleep (Win7)

[kulivontot]

Sometimes (maybe 1/10 times) the brightness controls stop working when I resume from sleep. Going to the windows mobility center, the brightness control slider completely disappears, indicating that the operating system has acknowledged that the brightness control is not there at all. Happens both with and without the power management/system interface driver/hotkeys installed. I'm guessing it's not a thinkpad specific problem, but a win7 one.