I just bit the bullet and installed CentOS 5 on my work desktop, and although I have two monitors and a card that supports them, I cannot get the display configuration to work with both as a continuous (spanning) desktop. I have tried using the correct (autodetected) monitor type (digital and analog), a generic LCD with 1280x1024, nothing works. Every time I set the configuration, the X server fails to restart and I wind up with single-head monitoring (duplicate displays on both screens).
Here's what I have for an xorg.conf file (now):
# Xorg configuration created by system-config-display
Section "ServerLayout" Identifier "single head configuration" Screen 0 "Screen0" 0 0 InputDevice "Keyboard0" "CoreKeyboard" EndSection
Section "InputDevice" Identifier "Keyboard0" Driver "kbd" Option "XkbModel" "pc105" Option "XkbLayout" "us" EndSection
Section "Device" Identifier "Videocard0" Driver "vesa" EndSection
Section "Screen" Identifier "Screen0" Device "Videocard0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 Modes "1280x1024" "1280x960" "1280x800" "1152x864" "1024x768" "800x600" "640x480" EndSubSection EndSection
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The strangest part is that system-config-display comes up with the right video card and the right monitor type, but I don't see either one here....