Disabling Laptop LCD

[sherman]

I am running debian lenny on my laptop.
Somehow (I'm honestly not quite sure how!!) I have managed to get my external samsung 931BW monitor (VGA) to be primary, and display at its native resolution (1440x900). However, the internal LCD is still displaying (cloned output).
I want to run beryl on this laptop. Beryl works, however it is a tad bit slow - just enough to make it unusable for day to day useage. I'm thinking that turning off the laptop monitor will increase performance. Would this be a reasonable assumption?
AIGLX is being used for rendering (at least I hope it is!!)
The graphics is Intel 945GM/950GMA.
Beryl runs perfectly when no external monitor is present (on different dirstros admittedly).

# /etc/X11/xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the /etc/X11/xorg.conf manual page.
# (Type "man /etc/X11/xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#   sudo dpkg-reconfigure -phigh xserver-xorg

Section "Files"
	FontPath	"/usr/share/fonts/X11/misc"
	FontPath	"/usr/X11R6/lib/X11/fonts/misc"
	FontPath	"/usr/share/fonts/X11/cyrillic"
	FontPath	"/usr/X11R6/lib/X11/fonts/cyrillic"
	FontPath	"/usr/share/fonts/X11/100dpi/:unscaled"
	FontPath	"/usr/X11R6/lib/X11/fonts/100dpi/:unscaled"
	FontPath	"/usr/share/fonts/X11/75dpi/:unscaled"
	FontPath	"/usr/X11R6/lib/X11/fonts/75dpi/:unscaled"
	FontPath	"/usr/share/fonts/X11/Type1"
	FontPath	"/usr/X11R6/lib/X11/fonts/Type1"
	FontPath	"/usr/share/fonts/X11/100dpi"
	FontPath	"/usr/X11R6/lib/X11/fonts/100dpi"
	FontPath	"/usr/share/fonts/X11/75dpi"
	FontPath	"/usr/X11R6/lib/X11/fonts/75dpi"
	# path to defoma fonts
	FontPath	"/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
EndSection

Section "Module"
	Load	"i2c"
	Load	"bitmap"
	Load	"ddc"
	Load	"dri"
	Load	"extmod"
	Load	"freetype"
	Load	"glx"
	Load	"int10"
	Load	"vbe"
EndSection

Section "Extensions"
   Option   "Composite"   "Enable"
EndSection

Section "InputDevice"
	Identifier	"Generic Keyboard"
	Driver		"kbd"
	Option		"CoreKeyboard"
	Option		"XkbRules"	"xorg"
	Option		"XkbModel"	"pc104"
	Option		"XkbLayout"	"us"
EndSection

Section "InputDevice"
	Identifier	"Configured Mouse"
	Driver		"mouse"
	Option		"CorePointer"
	Option		"Device"		"/dev/input/mice"
	Option		"Protocol"		"ImPS/2"
	Option		"Emulate3Buttons"	"true"
EndSection

Section "InputDevice"
	Identifier	"Synaptics Touchpad"
	Driver		"synaptics"
	Option		"SendCoreEvents"	"true"
	Option		"Device"		"/dev/psaux"
	Option		"Protocol"		"auto-dev"
	Option		"HorizScrollDelta"	"0"
EndSection

Section "Monitor"
    Identifier "Internal LCD"
    Option "DPMS"
EndSection

Section "Monitor"
    Identifier "External Monitor"
    VendorName "Samsung"
    ModelName "Syncmaster 931BW"
    HorizSync 31.5-90
    VertRefresh 60
    # modeline generated by gtf(1) [handled by XFdrake]
    ModeLine "1440x900_60"  106.47  1440 1520 1672 1904  900 901 904 932  -HSync +Vsync
EndSection

Section "Device"
    Identifier "Intel 950GMA 0"
    Driver "i810"
    BusID  "PCI:0:2:0"
    Option "MonitorLayout" "CRT,LFD"
    Option "May_Need_ForceBIOS" "1"
    Option "XaaNoOffscreenPixmaps" "1"
    Option "DDCMode" "True"
    Option "AddARGBGLXVisuals" "true"
    Option "AllowGLXWithComposite" "true"
    Screen 0
EndSection

Section "Device"
    Identifier "Intel 9GMA"
    VendorName "Intel Corp."
    BoardName "Intel 945"
    Driver "i810"
    BusID  "PCI:0:2:1"
    Option "May_Need_ForceBIOS" "1"
    Option "XaaNoOffscreenPixmaps" "1"
    Option "AddARGBGLXVisuals" "true"
    Option "AllowGLXWithComposite" "true"
    Option "DDCMode" "True"
    Screen 1
EndSection

Section "Screen"
    Identifier "Screen 0"
    Device "Intel 950GMA 0"
    Monitor "Internal LCD
    DefaultColorDepth 24

    Subsection "Display
	Depth 24
	Modes "1280x800"
    EndSubsection
EndSection

Section "Screen"
    Identifier "Screen 1"
    Device "Intel 9GMA"
    Monitor "External Monitor"
    DefaultColorDepth 24

    Subsection "Display"
        Depth 24
        Modes "1440x900"
    EndSubsection
EndSection

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen	0	"Screen 0"
	Screen  1	"Screen 1" LeftOf "Screen 0"
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
	InputDevice	"Synaptics Touchpad"
	Option 		"AIGLX"	"On"
EndSection

Section "DRI"
	Mode	0666
EndSection

Can anyone help?

PS: Fn+F4 (toggle to change output) is NOT working

[iwanabeguru]

delete the lines from server layout section which refer to lcd.

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen	0	"Screen 0"   <--- DELETE THIS LINE
	Screen  1	"Screen 1" LeftOf "Screen 0"
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
	InputDevice	"Synaptics Touchpad"
	Option 		"AIGLX"	"On"
EndSection

[sherman]

Unfortunately, after a bit of playing, X refuses to load if the "Screen 0" reference is not in the ServerLayout section.
It says somthing about no screen found etc.