Screen is dimmed....

[Antonio M]

when I start any video player on F10 my screen is dimmed on my laptop,
as energy manager would understand that is running on battery even if
I am connected to the wall socket!!!
This started after latest kernel updates: to recover from it I must
log out and then log in.
Any idea?? shall I file a bug (I guess against kernel..)???

-- 
Antonio Montagnani
Skype : antoniomontag