These are the relevant portions of my /etc/x.org.conf
Section "ServerLayout" Identifier "single head configuration" Screen 0 "Screen0" 0 0 InputDevice "Mouse0" "CorePointer" InputDevice "Keyboard0" "CoreKeyboard" RgbPath "/usr/X11R6/lib/X11/rgb" FontPath "unix/:7100" EndSection Section "Module" Load "dbe" Load "extmod" Load "fbdevhw" Load "glx" Load "record" Load "freetype" Load "type1" Load "dri" EndSection Section "InputDevice" Identifier "Keyboard0" Driver "kbd" Option "XkbModel" "pc105" Option "XkbLayout" "us" EndSection Section "InputDevice" Identifier "Mouse0" Driver "mouse" Option "Protocol" "IMPS/2" Option "Device" "/dev/input/mice" Option "ZAxisMapping" "4 5" Option "Emulate3Buttons" "yes" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Monitor Vendor" ModelName "Monitor 1024x768" HorizSync 31.5 - 57.0 VertRefresh 50.0 - 70.0 Option "dpms" EndSection Section "Device" Identifier "Videocard0" Driver "radeon" VendorName "Videocard vendor" BoardName "ATI Radeon IGP330M/340M/350M" EndSection Section "Screen" Identifier "Screen0" Device "Videocard0" Monitor "Monitor0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 16 Modes "800x600" "640x480" EndSubSection SubSection "Display" Viewport 0 0 Depth 24 Modes "1024x768" "800x600" "640x480" EndSubSection EndSection Section "DRI" Group 0 Mode 0666 EndSection