Is there a way to query the power status of an Xorg/X11 display from command line? I want to know if my laptop LCD is powered on after the screen saver--apparently the backlight is still on. This is despite my gnome-screensaver-preferences setting that after 5 minutes of idling, the display is supposed to go to sleep. I am using Debian 6 and whatever x server comes with it.
I see that
upower utility has some nifty switches, but they are not documented.