I've recently bought an HP Pavilion dv3-2150ep and I'm having a hard time getting the volume control display to work as expected. The control is a back-lit touch-sensitive bar above the keyboard. Now the buttons to turn the volume up and down actually do it, but the lightning is not changing at all. The mute button does change color when toggled.
I'm not sure if I'm missing any drivers here (I've installed all of those on the HP support page that seem to have something to do with sound and/or display) or if I have to activate this somewhere.