Laptop screen on in X while plugged into external screen
I have CentOS 4.7 installed on a Dell Inspiron notebook. The installation is pretty much a bare bone installation with just the X Window System. It does not have any graphical interfaces like GNOME or KDE. At boot it simply uses "startx" to load a game called StepMania in run level 3.
(I don't have the specific Inspiron model as I don't have it in-front of me at the moment)
When in the command line or during boot the notebooks screen is turned off like it should be, and I'm able to use the the change screen function to switch between the laptop and the external VGA screen plugged into it.
When I start StepMania through X, the notebooks screen gets turned on, almost if it was in some sort of "dual screen" mode. There is nothing on the notebooks screen, but it gets illuminated and will not turn off, even when I close the lid. Using the screen function does absolutely nothing.
Is there any way I can configure X to use the external screen and ignore the internal one? Perhaps with a particular Xorg configuration?