Take a look at the contents of the /etc/X11/xorg.conf file I've got on
my system, hopefully it will help. (It was generated by the nVidia
driver installation script and has compositing enabled):
###########################################################
Section "ServerLayout"
Identifier "single head configuration"
Screen 0 "Screen0" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "Files"
EndSection
Section "ServerFlags"
Option "AIGLX" "on"
EndSection
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section "InputDevice"
# keyboard added by rhpxl
Identifier "Keyboard0"
Driver "kbd"
Option "XkbModel" "pc105"
Option "XkbLayout" "us"
EndSection
Section "Monitor"
Identifier "Monitor0"
ModelName "Acer AL1916W"
HorizSync 30.0 - 82.0
VertRefresh 56.0 - 76.0
Option "dpms"
EndSection
Section "Device"
Identifier "Videocard0"
Driver "nvidia"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
Option "ignoreABI"
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
Section "Extensions"
Option "Composite" "Enable"
EndSection
###########################################################