Open Source Video

# /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/X11/fonts/misc”
FontPath “/usr/share/X11/fonts/cyrillic”
FontPath “/usr/share/X11/fonts/100dpi/:unscaled”
FontPath “/usr/share/X11/fonts/75dpi/:unscaled”
FontPath “/usr/share/X11/fonts/Type1”
FontPath “/usr/share/X11/fonts/100dpi”
FontPath “/usr/share/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 “type1”
Load “vbe”
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” “ExplorerPS/2”
Option “ZAxisMapping” “4 5”
Option “Emulate3Buttons” “true”
EndSection

Section “InputDevice”
Driver “wacom”
Identifier “stylus”
Option “Device” “/dev/wacom” # Change to
# /dev/input/event
# for USB
Option “Type” “stylus”
Option “ForceDevice” “ISDV4” # Tablet PC ONLY
EndSection

Section “InputDevice”
Driver “wacom”
Identifier “eraser”
Option “Device” “/dev/wacom” # Change to
# /dev/input/event
# for USB
Option “Type” “eraser”
Option “ForceDevice” “ISDV4” # Tablet PC ONLY
EndSection

Section “InputDevice”
Driver “wacom”
Identifier “cursor”
Option “Device” “/dev/wacom” # Change to
# /dev/input/event
# for USB
Option “Type” “cursor”
Option “ForceDevice” “ISDV4” # Tablet PC ONLY
EndSection

Section “Device”
Identifier “DVIport”
Boardname “ATI Technologies, Inc. RV280 [Radeon 9200 PRO]”
Driver “ati”
BusID “PCI:1:0:0”
Screen 0
EndSection

Section “Device”
Identifier “VGAport”
Boardname “ATI Technologies, Inc. RV280 [Radeon 9200 PRO]”
Driver “ati”
BusID “PCI:1:0:0”
Screen 1
EndSection

Section “Monitor”
Identifier “GDM-400PST-L”
Option “DPMS”
EndSection

Section “Monitor”
Identifier “GDM-400PST-R”
Option “DPMS”
EndSection

Section “Screen”
Identifier “VGAScreen”
Device “VGAport”
Monitor “GDM-400PST-R”
DefaultDepth 24
SubSection “Display”
Depth 1
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 4
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 8
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 15
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 16
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 24
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
EndSection

Section “Screen”
Identifier “DVIScreen”
Device “DVIport”
Monitor “GDM-400PST-L”
DefaultDepth 24
SubSection “Display”
Depth 1
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 4
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 8
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 15
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 16
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
SubSection “Display”
Depth 24
Modes “1280×1024” “1152×864” “1024×768” “832×624” “800×600” “720×400” “640×480”
EndSubSection
EndSection

Section “ServerLayout”
Identifier “Default Layout”
Screen “VGAScreen”
Screen “DVIScreen” LeftOf “VGAScreen”
InputDevice “Generic Keyboard”
InputDevice “Configured Mouse”
InputDevice “stylus” “SendCoreEvents”
InputDevice “cursor” “SendCoreEvents”
InputDevice “eraser” “SendCoreEvents”

Option “Xinerama” “on”
Option “Clone” “on”
EndSection

Section “DRI”
Mode 0666
EndSection

The xorg.conf file isn’t that hard to understand, once you grasp the relationship between the sections for Monitor(s), Mode(s), Screen(s), Device(s) and the ServerLayout section.
For a single head setup it looks like this:

Read this diagram bottom-up as: A given X-server layout consists of 1 screen, screen 1 (number 0) has a device (number 0) and a monitor (number 0), Device 0 is defined in the Section “Device” with Identifier “Device[0]”.
Monitor 0 is defined in the Section “Monitor” with identifier “Monitor[0]” and uses Modes[0], defined in de Section “Modes” with Identifier “Modes[0]”.
For a xinerama layout you have to ‘repeat’ this excercise for screen 2 and eventually screen 3, 4, 5 …

Those Identifiers are just strings you can name them what you want, as long as you make sure that when you reference a given identifier in another section you use the exact same string.