xorg.conf(4)
INTRODUCTION
Xorg supports several mechanisms for supplying/obtaining configuration
and run-time parameters: command line options, environment variables,
the xorg.conf configuration file, auto-detection, and fallback
defaults. When the same information is supplied in more than one way,
the highest precedence mechanism is used. The list of mechanisms is
ordered from highest precedence to lowest. Note that not all parame-
ters can be supplied via all methods. The available command line
options and environment variables (and some defaults) are described in
the Xserver(1) and Xorg(1) manual pages. Most configuration file
parameters, with their defaults, are described below. Driver and mod-
ule specific configuration parameters are described in the relevant
driver or module manual page.
DESCRIPTION
Xorg uses a configuration file called xorg.conf for its initial setup.
This configuration file is searched for in the following places when
the server is started as a normal user:
/etc/X11/<cmdline>
/usr/X11R6/etc/X11/<cmdline>
/etc/X11/$XORGCONFIG
/usr/X11R6/etc/X11/$XORGCONFIG
/etc/X11/xorg.conf-4
/etc/X11/xorg.conf
/etc/xorg.conf
/usr/X11R6/etc/X11/xorg.conf.<hostname>
/usr/X11R6/etc/X11/xorg.conf-4
/usr/X11R6/etc/X11/xorg.conf
/usr/X11R6/lib/X11/xorg.conf.<hostname>
/usr/X11R6/lib/X11/xorg.conf-4
/usr/X11R6/lib/X11/xorg.conf
where <cmdline> is a relative path (with no ".." components) specified
with the -config command line option, $XORGCONFIG is the relative path
(with no ".." components) specified by that environment variable, and
<hostname> is the machine's hostname as reported by gethostname(3).
When the Xorg server is started by the "root" user, the config file
search locations are as follows:
<cmdline>
/etc/X11/<cmdline>
/usr/X11R6/etc/X11/<cmdline>
$XORGCONFIG
/etc/X11/$XORGCONFIG
/usr/X11R6/etc/X11/$XORGCONFIG
$HOME/xorg.conf
/etc/X11/xorg.conf-4
/etc/X11/xorg.conf
/etc/xorg.conf
/usr/X11R6/etc/X11/xorg.conf.<hostname>
present in any order. Each section has the form:
Section "SectionName"
SectionEntry
...
EndSection
The section names are:
Files File pathnames
ServerFlags Server flags
Module Dynamic module loading
InputDevice Input device description
Device Graphics device description
VideoAdaptor Xv video adaptor description
Monitor Monitor description
Modes Video modes descriptions
Screen Screen configuration
ServerLayout Overall layout
DRI DRI-specific configuration
Vendor Vendor-specific configuration
The following obsolete section names are still recognised for compati-
bility purposes. In new config files, the InputDevice section should
be used instead.
Keyboard Keyboard configuration
Pointer Pointer/mouse configuration
The old XInput section is no longer recognised.
The ServerLayout sections are at the highest level. They bind together
the input and output devices that will be used in a session. The input
devices are described in the InputDevice sections. Output devices usu-
ally consist of multiple independent components (e.g., and graphics
board and a monitor). These multiple components are bound together in
the Screen sections, and it is these that are referenced by the Server-
Layout section. Each Screen section binds together a graphics board
and a monitor. The graphics boards are described in the Device sec-
tions, and the monitors are described in the Monitor sections.
Config file keywords are case-insensitive, and "_" characters are
ignored. Most strings (including Option names) are also case-insensi-
tive, and insensitive to white space and "_" characters.
Each config file entry usually takes up a single line in the file.
They consist of a keyword, which is possibly followed by one or more
arguments, with the number and types of the arguments depending on the
keyword. The argument types are:
Integer an integer number in decimal, hex or octal
Real a floating point number
Boolean a boolean value (see below)
Frequency a frequency value (see below)
Note that all Option values, not just strings, must be enclosed in
quotes.
Boolean options may optionally have a value specified. When no value
is specified, the option's value is TRUE. The following boolean option
values are recognised as TRUE:
1, on, true, yes
and the following boolean option values are recognised as FALSE:
0, off, false, no
If an option name is prefixed with "No", then the option value is
negated.
Example: the following option entries are equivalent:
Option "Accel" "Off"
Option "NoAccel"
Option "NoAccel" "On"
Option "Accel" "false"
Option "Accel" "no"
Frequency option values consist of a real number that is optionally
followed by one of the following frequency units:
Hz, k, kHz, M, MHz
When the unit name is omitted, the correct units will be determined
from the value and the expectations of the appropriate range of the
value. It is recommended that the units always be specified when using
frequency option values to avoid any errors in determining the value.
FILES SECTION
The Files section is used to specify some path names required by the
server. Some of these paths can also be set from the command line (see
Xserver(1) and Xorg(1)). The command line settings override the values
specified in the config file. The Files section is optional, as are
all of the entries that may appear in it.
The entries that can appear in this section are:
FontPath "path"
sets the search path for fonts. This path is a comma separated
list of font path elements which the Xorg server searches for
font databases. Multiple FontPath entries may be specified, and
they will be concatenated to build up the fontpath used by the
server. Font path elements may be either absolute directory
/usr/X11R6/lib/X11/fonts/misc/
/usr/X11R6/lib/X11/fonts/Speedo/
/usr/X11R6/lib/X11/fonts/Type1/
/usr/X11R6/lib/X11/fonts/CID/
/usr/X11R6/lib/X11/fonts/75dpi/
/usr/X11R6/lib/X11/fonts/100dpi/
The recommended font path contains the following font path ele-
ments:
/usr/X11R6/lib/X11/fonts/local/
/usr/X11R6/lib/X11/fonts/misc/
/usr/X11R6/lib/X11/fonts/75dpi/:unscaled
/usr/X11R6/lib/X11/fonts/100dpi/:unscaled
/usr/X11R6/lib/X11/fonts/Type1/
/usr/X11R6/lib/X11/fonts/CID/
/usr/X11R6/lib/X11/fonts/Speedo/
/usr/X11R6/lib/X11/fonts/75dpi/
/usr/X11R6/lib/X11/fonts/100dpi/
Font path elements that are found to be invalid are removed from
the font path when the server starts up.
RGBPath "path"
sets the path name for the RGB color database. When this entry
is not specified in the config file, the server falls back to
the compiled-in default RGB path, which is:
/usr/X11R6/lib/X11/rgb
Note that an implicit .txt is added to this path if the server was com-
piled to use text rather than binary format RGB color databases.
ModulePath "path"
sets the search path for loadable Xorg server modules. This
path is a comma separated list of directories which the Xorg
server searches for loadable modules loading in the order speci-
fied. Multiple ModulePath entries may be specified, and they
will be concatenated to build the module search path used by the
server.
SERVERFLAGS SECTION
The ServerFlags section is used to specify some global Xorg server
options. All of the entries in this section are Options, although for
compatibility purposes some of the old style entries are still recog-
nised. Those old style entries are not documented here, and using them
is discouraged. The ServerFlags section is optional, as are the
entries that may be specified in it.
Options specified in this section (with the exception of the "Default-
ServerLayout" Option) may be overridden by Options specified in the
option unless you are debugging an Xorg server problem and know
how to deal with the consequences.
Option "DontVTSwitch" "boolean"
This disallows the use of the Ctrl+Alt+Fn sequence (where Fn
refers to one of the numbered function keys). That sequence is
normally used to switch to another "virtual terminal" on operat-
ing systems that have this feature. When this option is
enabled, that key sequence has no special meaning and is passed
to clients. Default: off.
Option "DontZap" "boolean"
This disallows the use of the Ctrl+Alt+Backspace sequence. That
sequence is normally used to terminate the Xorg server. When
this option is enabled, that key sequence has no special meaning
and is passed to clients. Default: off.
Option "DontZoom" "boolean"
This disallows the use of the Ctrl+Alt+Keypad-Plus and
Ctrl+Alt+Keypad-Minus sequences. These sequences allows you to
switch between video modes. When this option is enabled, those
key sequences have no special meaning and are passed to clients.
Default: off.
Option "DisableVidModeExtension" "boolean"
This disables the parts of the VidMode extension used by the
xvidtune client that can be used to change the video modes.
Default: the VidMode extension is enabled.
Option "AllowNonLocalXvidtune" "boolean"
This allows the xvidtune client (and other clients that use the
VidMode extension) to connect from another host. Default: off.
Option "DisableModInDev" "boolean"
This disables the parts of the Xorg-Misc extension that can be
used to modify the input device settings dynamically. Default:
that functionality is enabled.
Option "AllowNonLocalModInDev" "boolean"
This allows a client to connect from another host and change
keyboard and mouse settings in the running server. Default:
off.
Option "AllowMouseOpenFail" "boolean"
This allows the server to start up even if the mouse device
can't be opened/initialised. Default: false.
Option "VTInit" "command"
Runs command after the VT used by the server has been opened.
The command string is passed to "/bin/sh -c", and is run with
the real user's id with stdin and stdout set to the VT. The
purpose of this option is to allow system dependent VT initiali-
Option "BlankTime" "time"
sets the inactivity timeout for the blanking phase of the
screensaver. time is in minutes. This is equivalent to the
Xorg server's `-s' flag, and the value can be changed at run-
time with xset(1). Default: 10 minutes.
Option "StandbyTime" "time"
sets the inactivity timeout for the "standby" phase of DPMS
mode. time is in minutes, and the value can be changed at run-
time with xset(1). Default: 20 minutes. This is only suitable
for VESA DPMS compatible monitors, and may not be supported by
all video drivers. It is only enabled for screens that have the
"DPMS" option set (see the MONITOR section below).
Option "SuspendTime" "time"
sets the inactivity timeout for the "suspend" phase of DPMS
mode. time is in minutes, and the value can be changed at run-
time with xset(1). Default: 30 minutes. This is only suitable
for VESA DPMS compatible monitors, and may not be supported by
all video drivers. It is only enabled for screens that have the
"DPMS" option set (see the MONITOR section below).
Option "OffTime" "time"
sets the inactivity timeout for the "off" phase of DPMS mode.
time is in minutes, and the value can be changed at run-time
with xset(1). Default: 40 minutes. This is only suitable for
VESA DPMS compatible monitors, and may not be supported by all
video drivers. It is only enabled for screens that have the
"DPMS" option set (see the MONITOR section below).
Option "Pixmap" "bpp"
This sets the pixmap format to use for depth 24. Allowed values
for bpp are 24 and 32. Default: 32 unless driver constraints
don't allow this (which is rare). Note: some clients don't
behave well when this value is set to 24.
Option "PC98" "boolean"
Specify that the machine is a Japanese PC-98 machine. This
should not be enabled for anything other than the Japanese-spe-
cific PC-98 architecture. Default: auto-detected.
Option "NoPM" "boolean"
Disables something to do with power management events. Default:
PM enabled on platforms that support it.
Option "Xinerama" "boolean"
enable or disable XINERAMA extension. Default is disabled.
Option "AllowDeactivateGrabs" "boolean"
This option enables the use of the Ctrl+Alt+Keypad-Divide key
sequence to deactivate any active keyboard and mouse grabs.
Option "HandleSpecialKeys" "when"
This option controls when the server uses the builtin handler to
process special key combinations (such as Ctrl+Alt+Backspace).
Normally the XKEYBOARD extension keymaps will provide mappings
for each of the special key combinations, so the builtin handler
is not needed unless the XKEYBOARD extension is disabled. The
value of when can be Always, Never, or WhenNeeded. Default: Use
the builtin handler only if needed. The server will scan the
keymap for a mapping to the Terminate action and, if found, use
XKEYBOARD for processing actions, otherwise the builtin handler
will be used.
MODULE SECTION
The Module section is used to specify which Xorg server modules should
be loaded. This section is ignored when the Xorg server is built in
static form. The types of modules normally loaded in this section are
Xorg server extension modules, and font rasteriser modules. Most other
module types are loaded automatically when they are needed via other
mechanisms. The Module section is optional, as are all of the entries
that may be specified in it.
Entries in this section may be in two forms. The first and most com-
monly used form is an entry that uses the Load keyword, as described
here:
Load "modulename"
This instructs the server to load the module called modulename.
The module name given should be the module's standard name, not
the module file name. The standard name is case-sensitive, and
does not include the "lib" prefix, or the ".a", ".o", or ".so"
suffixes.
Example: the Type 1 font rasteriser can be loaded with the fol-
lowing entry:
Load "type1"
The second form of entry is a SubSection, with the subsection name
being the module name, and the contents of the SubSection being Options
that are passed to the module when it is loaded.
Example: the extmod module (which contains a miscellaneous group of
server extensions) can be loaded, with the Xorg-DGA extension disabled
by using the following entry:
SubSection "extmod"
Option "omit XFree86-DGA"
EndSubSection
Modules are searched for in each directory specified in the ModulePath
search path, and in the drivers, input, extensions, fonts, and internal
subdirectories of each of those directories. In addition to this,
INPUTDEVICE SECTION
The config file may have multiple InputDevice sections. There will
normally be at least two: one for the core (primary) keyboard, and one
of the core pointer. If either of these two is missing, a default con-
figuration for the missing ones will be used. Currently the default
configuration may not work as expected on all platforms.
InputDevice sections have the following format:
Section "InputDevice"
Identifier "name"
Driver "inputdriver"
options
...
EndSection
The Identifier and Driver entries are required in all InputDevice sec-
tions. All other entries are optional.
The Identifier entry specifies the unique name for this input device.
The Driver entry specifies the name of the driver to use for this input
device. When using the loadable server, the input driver module
"inputdriver" will be loaded for each active InputDevice section. An
InputDevice section is considered active if it is referenced by an
active ServerLayout section, if it is referenced by the -keyboard or
-pointer command line options, or if it is selected implicitly as the
core pointer or keyboard device in the absence of such explicit refer-
ences. The most commonly used input drivers are "keyboard" and
"mouse".
In the absence of an explicitly specified core input device, the first
InputDevice marked as CorePointer (or CoreKeyboard) is used. If there
is no match there, the first InputDevice that uses the "mouse" (or
"keyboard" or "kbd") driver is used. The final fallback is to use
built-in default configurations.
InputDevice sections recognise some driver-independent Options, which
are described here. See the individual input driver manual pages for a
description of the device-specific options.
Option "CorePointer"
When this is set, the input device is installed as the core
(primary) pointer device. There must be exactly one core
pointer. If this option is not set here, or in the ServerLayout
section, or from the -pointer command line option, then the
first input device that is capable of being used as a core
pointer will be selected as the core pointer. This option is
implicitly set when the obsolete Pointer section is used.
Option "CoreKeyboard"
When this is set, the input device is to be installed as the
core (primary) keyboard device. There must be exactly one core
Option "HistorySize" "number"
Sets the motion history size. Default: 0.
Option "SendDragEvents" "boolean"
???
DEVICE SECTION
The config file may have multiple Device sections. There must be at
least one, for the video card being used.
Device sections have the following format:
Section "Device"
Identifier "name"
Driver "driver"
entries
...
EndSection
The Identifier and Driver entries are required in all Device sections.
All other entries are optional.
The Identifier entry specifies the unique name for this graphics
device. The Driver entry specifies the name of the driver to use for
this graphics device. When using the loadable server, the driver mod-
ule "driver" will be loaded for each active Device section. A Device
section is considered active if it is referenced by an active Screen
section.
Device sections recognise some driver-independent entries and Options,
which are described here. Not all drivers make use of these driver-
independent entries, and many of those that do don't require them to be
specified because the information is auto-detected. See the individual
graphics driver manual pages for further information about this, and
for a description of the device-specific options. Note that most of
the Options listed here (but not the other entries) may be specified in
the Screen section instead of here in the Device section.
BusID "bus-id"
This specifies the bus location of the graphics card. For
PCI/AGP cards, the bus-id string has the form
PCI:bus:device:function (e.g., "PCI:1:0:0" might be appropriate
for an AGP card). This field is usually optional in single-head
configurations when using the primary graphics card. In multi-
head configurations, or when using a secondary graphics card in
a single-head configuration, this entry is mandatory. Its main
purpose is to make an unambiguous connection between the device
section and the hardware it is representing. This information
can usually be found by running the Xorg server with the -scan-
pci command line option.
Screen number
mentation recommends that you do.
Ramdac "ramdac-type"
This optional entry specifies the type of RAMDAC used on the
graphics board. This is only used by a few of the drivers, and
in most cases it is not required because the drivers will probe
the hardware to determine the RAMDAC type where possible. Don't
specify it unless the driver-specific documentation recommends
that you do.
DacSpeed speed
DacSpeed speed-8 speed-16 speed-24 speed-32
This optional entry specifies the RAMDAC speed rating (which is
usually printed on the RAMDAC chip). The speed is in MHz. When
one value is given, it applies to all framebuffer pixel sizes.
When multiple values are give, they apply to the framebuffer
pixel sizes 8, 16, 24 and 32 respectively. This is not used by
many drivers, and only needs to be specified when the speed rat-
ing of the RAMDAC is different from the defaults built in to
driver, or when the driver can't auto-detect the correct
defaults. Don't specify it unless the driver-specific documen-
tation recommends that you do.
Clocks clock ...
specifies the pixel that are on your graphics board. The clocks
are in MHz, and may be specified as a floating point number.
The value is stored internally to the nearest kHz. The ordering
of the clocks is important. It must match the order in which
they are selected on the graphics board. Multiple Clocks lines
may be specified, and each is concatenated to form the list.
Most drivers do not use this entry, and it is only required for
some older boards with non-programmable clocks. Don't specify
this entry unless the driver-specific documentation explicitly
recommends that you do.
ClockChip "clockchip-type"
This optional entry is used to specify the clock chip type on
graphics boards which have a programmable clock generator. Only
a few Xorg drivers support programmable clock chips. For
details, see the appropriate driver manual page.
VideoRam mem
This optional entry specifies the amount of video ram that is
installed on the graphics board. This is measured in kBytes. In
most cases this is not required because the Xorg server probes
the graphics board to determine this quantity. The driver-spe-
cific documentation should indicate when it might be needed.
BiosBase baseaddress
This optional entry specifies the base address of the video BIOS
for the VGA board. This address is normally auto-detected, and
ChipID id
This optional entry specifies a numerical ID representing the
chip type. For PCI cards, it is usually the device ID. This
can be used to override the auto-detection, but that should only
be done when the driver-specific documentation recommends it.
ChipRev rev
This optional entry specifies the chip revision number. This
can be used to override the auto-detection, but that should only
be done when the driver-specific documentation recommends it.
TextClockFreq freq
This optional entry specifies the pixel clock frequency that is
used for the regular text mode. The frequency is specified in
MHz. This is rarely used.
Options
Option flags may be specified in the Device sections. These
include driver-specific options and driver-independent options.
The former are described in the driver-specific documentation.
Some of the latter are described below in the section about the
Screen section, and they may also be included here.
VIDEOADAPTOR SECTION
Nobody wants to say how this works. Maybe nobody knows ...
MONITOR SECTION
The config file may have multiple Monitor sections. There should nor-
mally be at least one, for the monitor being used, but a default con-
figuration will be created when one isn't specified.
Monitor sections have the following format:
Section "Monitor"
Identifier "name"
entries
...
EndSection
The only mandatory entry in a Monitor section is the Identifier entry.
The Identifier entry specifies the unique name for this monitor. The
Monitor section provides information about the specifications of the
monitor, monitor-specific Options, and information about the video
modes to use with the monitor. Specifying video modes is optional
because the server now has a built-in list of VESA standard modes.
When modes are specified explicitly in the Monitor section (with the
Modes, ModeLine, or UseModes keywords), built-in modes with the same
names are not included. Built-in modes with different names are, how-
ever, still implicitly included.
units of kHz. They may be specified in MHz or Hz if MHz or Hz
is added to the end of the line. The data given here is used by
the Xorg server to determine if video modes are within the spec-
ifications of the monitor. This information should be available
in the monitor's handbook. If this entry is omitted, a default
range of 28-33kHz is used.
VertRefresh vertrefresh-range
gives the range(s) of vertical refresh frequencies supported by
the monitor. vertrefresh-range may be a comma separated list of
either discrete values or ranges of values. A range of values
is two values separated by a dash. By default the values are in
units of Hz. They may be specified in MHz or kHz if MHz or kHz
is added to the end of the line. The data given here is used by
the Xorg server to determine if video modes are within the spec-
ifications of the monitor. This information should be available
in the monitor's handbook. If this entry is omitted, a default
range of 43-72Hz is used.
DisplaySize width height
This optional entry gives the width and height, in millimetres,
of the picture area of the monitor. If given this is used to
calculate the horizontal and vertical pitch (DPI) of the screen.
Gamma gamma-value
Gamma red-gamma green-gamma blue-gamma
This is an optional entry that can be used to specify the gamma
correction for the monitor. It may be specified as either a
single value or as three separate RGB values. The values should
be in the range 0.1 to 10.0, and the default is 1.0. Not all
drivers are capable of using this information.
UseModes "modesection-id"
Include the set of modes listed in the Modes section called mod-
esection-id. This make all of the modes defined in that section
available for use by this monitor.
Mode "name"
This is an optional multi-line entry that can be used to provide
definitions for video modes for the monitor. In most cases this
isn't necessary because the built-in set of VESA standard modes
will be sufficient. The Mode keyword indicates the start of a
multi-line video mode description. The mode description is ter-
minated with the EndMode keyword. The mode description consists
of the following entries:
DotClock clock
is the dot (pixel) clock rate to be used for the mode.
HTimings hdisp hsyncstart hsyncend htotal
specifies the horizontal timings for the mode.
select the composite sync polarity.
HSkew hskew
specifies the number of pixels (towards the right edge of
the screen) by which the display enable signal is to be
skewed. Not all drivers use this information. This option
might become necessary to override the default value sup-
plied by the server (if any). "Roving" horizontal lines
indicate this value needs to be increased. If the last few
pixels on a scan line appear on the left of the screen, this
value should be decreased.
VScan vscan
specifies the number of times each scanline is painted on
the screen. Not all drivers use this information. Values
less than 1 are treated as 1, which is the default. Gener-
ally, the "DoubleScan" Flag mentioned above doubles this
value.
ModeLine "name" mode-description
This entry is a more compact version of the Mode entry, and it
also can be used to specify video modes for the monitor. is a
single line format for specifying video modes. In most cases
this isn't necessary because the built-in set of VESA standard
modes will be sufficient.
The mode-description is in four sections, the first three of
which are mandatory. The first is the dot (pixel) clock. This
is a single number specifying the pixel clock rate for the mode
in MHz. The second section is a list of four numbers specifying
the horizontal timings. These numbers are the hdisp, hsync-
start, hsyncend, and htotal values. The third section is a list
of four numbers specifying the vertical timings. These numbers
are the vdisp, vsyncstart, vsyncend, and vtotal values. The
final section is a list of flags specifying other characteris-
tics of the mode. Interlace indicates that the mode is inter-
laced. DoubleScan indicates a mode where each scanline is dou-
bled. +HSync and -HSync can be used to select the polarity of
the HSync signal. +VSync and -VSync can be used to select the
polarity of the VSync signal. Composite can be used to specify
composite sync on hardware where this is supported. Addition-
ally, on some hardware, +CSync and -CSync may be used to select
the composite sync polarity. The HSkew and VScan options men-
tioned above in the Modes entry description can also be used
here.
Options
Some Option flags that may be useful to include in Monitor sec-
tions (when needed) include "DPMS", and "SyncOnGreen".
MODES SECTION
The Identifier entry specifies the unique name for this set of mode
descriptions. The other entries permitted in Modes sections are the
Mode and ModeLine entries that are described above in the Monitor sec-
tion.
SCREEN SECTION
The config file may have multiple Screen sections. There must be at
least one, for the "screen" being used. A "screen" represents the
binding of a graphics device (Device section) and a monitor (Monitor
section). A Screen section is considered "active" if it is referenced
by an active ServerLayout section or by the -screen command line
option. If neither of those is present, the first Screen section found
in the config file is considered the active one.
Screen sections have the following format:
Section "Screen"
Identifier "name"
Device "devid"
Monitor "monid"
entries
...
SubSection "Display"
entries
...
EndSubSection
...
EndSection
The Identifier and Device entries are mandatory. All others are
optional.
The Identifier entry specifies the unique name for this screen. The
Screen section provides information specific to the whole screen,
including screen-specific Options. In multi-head configurations, there
will be multiple active Screen sections, one for each head. The
entries available for this section are:
Device "device-id"
This mandatory entry specifies the Device section to be used for
this screen. This is what ties a specific graphics card to a
screen. The device-id must match the Identifier of a Device
section in the config file.
Monitor "monitor-id"
specifies which monitor description is to be used for this
screen. If a Monitor name is not specified, a default configu-
ration is used. Currently the default configuration may not
function as expected on all platforms.
VideoAdaptor "xv-id"
is for depth 24, where some hardware supports both a packed 24
bit framebuffer layout and a sparse 32 bit framebuffer layout.
Options
Various Option flags may be specified in the Screen section.
Some are driver-specific and are described in the driver docu-
mentation. Others are driver-independent, and will eventually
be described here.
Option "Accel"
Enables XAA (X Acceleration Architecture), a mechanism that
makes video cards' 2D hardware acceleration available to the
Xorg server. This option is on by default, but it may be neces-
sary to turn it off if there are bugs in the driver. There are
many options to disable specific accelerated operations, listed
below. Note that disabling an operation will have no effect if
the operation is not accelerated (whether due to lack of support
in the hardware or in the driver).
Option "BiosLocation" "address"
Set the location of the BIOS for the Int10 module. One may
select a BIOS of another card for posting or the legacy V_BIOS
range located at 0xc0000 or an alternative address (BUS_ISA).
This is only useful under very special circumstances and should
be used with extreme care.
Option "InitPrimary" "boolean"
Use the Int10 module to initialize the primary graphics card.
Normally, only secondary cards are soft-booted using the Int10
module, as the primary card has already been initialized by the
BIOS at boot time. Default: false.
Option "NoInt10" "boolean"
Disables the Int10 module, a module that uses the int10 call to
the BIOS of the graphics card to initialize it. Default: false.
Option "NoMTRR"
Disables MTRR (Memory Type Range Register) support, a feature of
modern processors which can improve video performance by a fac-
tor of up to 2.5. Some hardware has buggy MTRR support, and
some video drivers have been known to exhibit problems when
MTRR's are used.
Option "XaaNoCPUToScreenColorExpandFill"
Disables accelerated rectangular expansion blits from source
patterns stored in system memory (using a memory-mapped aper-
ture).
Option "XaaNoColor8x8PatternFillRect"
Disables accelerated fills of a rectangular region with a full-
color pattern.
aperture).
Option "XaaNoMono8x8PatternFillRect"
Disables accelerated fills of a rectangular region with a mono-
chrome pattern.
Option "XaaNoMono8x8PatternFillTrap"
Disables accelerated fills of a trapezoidal region with a mono-
chrome pattern.
Option "XaaNoOffscreenPixmaps"
Disables accelerated draws into pixmaps stored in offscreen
video memory.
Option "XaaNoPixmapCache"
Disables caching of patterns in offscreen video memory.
Option "XaaNoScanlineCPUToScreenColorExpandFill"
Disables accelerated rectangular expansion blits from source
patterns stored in system memory (one scan line at a time).
Option "XaaNoScanlineImageWriteRect"
Disables accelerated transfers of full-color rectangular pat-
terns from system memory to video memory (one scan line at a
time).
Option "XaaNoScreenToScreenColorExpandFill"
Disables accelerated rectangular expansion blits from source
patterns stored in offscreen video memory.
Option "XaaNoScreenToScreenCopy"
Disables accelerated copies of rectangular regions from one part
of video memory to another part of video memory.
Option "XaaNoSolidBresenhamLine"
Disables accelerated solid Bresenham line draws.
Option "XaaNoSolidFillRect"
Disables accelerated solid-color fills of rectangles.
Option "XaaNoSolidFillTrap"
Disables accelerated solid-color fills of Bresenham trapezoids.
Option "XaaNoSolidHorVertLine"
Disables accelerated solid horizontal and vertical line draws.
Option "XaaNoSolidTwoPointLine"
Disables accelerated solid line draws between two arbitrary
points.
Each Screen section may optionally contain one or more Display subsec-
tions. Those subsections provide depth/fbbpp specific configuration
Display subsections have the following format:
SubSection "Display"
Depth depth
entries
...
EndSubSection
Depth depth
This entry specifies what colour depth the Display subsection is
to be used for. This entry is usually specified, but it may be
omitted to create a match-all Display subsection or when wishing
to match only against the FbBpp parameter. The range of depth
values that are allowed depends on the driver. Most driver sup-
port 8, 15, 16 and 24. Some also support 1 and/or 4, and some
may support other values (like 30). Note: depth means the num-
ber of bits in a pixel that are actually used to determine the
pixel colour. 32 is not a valid depth value. Most hardware
that uses 32 bits per pixel only uses 24 of them to hold the
colour information, which means that the colour depth is 24, not
32.
FbBpp bpp
This entry specifies the framebuffer format this Display subsec-
tion is to be used for. This entry is only needed when provid-
ing depth 24 configurations that allow a choice between a 24 bpp
packed framebuffer format and a 32bpp sparse framebuffer format.
In most cases this entry should not be used.
Weight red-weight green-weight blue-weight
This optional entry specifies the relative RGB weighting to be
used for a screen is being used at depth 16 for drivers that
allow multiple formats. This may also be specified from the
command line with the -weight option (see Xorg(1)).
Virtual xdim ydim
This optional entry specifies the virtual screen resolution to
be used. xdim must be a multiple of either 8 or 16 for most
drivers, and a multiple of 32 when running in monochrome mode.
The given value will be rounded down if this is not the case.
Video modes which are too large for the specified virtual size
will be rejected. If this entry is not present, the virtual
screen resolution will be set to accommodate all the valid video
modes given in the Modes entry. Some drivers/hardware combina-
tions do not support virtual screens. Refer to the appropriate
driver-specific documentation for details.
ViewPort x0 y0
This optional entry sets the upper left corner of the initial
display. This is only relevant when the virtual screen resolu-
tion is different from the resolution of the initial video mode.
pad-Minus. When this entry is omitted, the valid modes refer-
enced by the appropriate Monitor section will be used. If the
Monitor section contains no modes, then the selection will be
taken from the built-in VESA standard modes.
Visual "visual-name"
This optional entry sets the default root visual type. This may
also be specified from the command line (see the Xserver(1) man
page). The visual types available for depth 8 are (default is
PseudoColor):
StaticGray
GrayScale
StaticColor
PseudoColor
TrueColor
DirectColor
The visual type available for the depths 15, 16 and 24 are
(default is TrueColor):
TrueColor
DirectColor
Not all drivers support DirectColor at these depths.
The visual types available for the depth 4 are (default is Stat-
icColor):
StaticGray
GrayScale
StaticColor
PseudoColor
The visual type available for the depth 1 (monochrome) is Stat-
icGray.
Black red green blue
This optional entry allows the "black" colour to be specified.
This is only supported at depth 1. The default is black.
White red green blue
This optional entry allows the "white" colour to be specified.
This is only supported at depth 1. The default is white.
Options
Option flags may be specified in the Display subsections. These
may include driver-specific options and driver-independent
options. The former are described in the driver-specific docu-
mentation. Some of the latter are described above in the sec-
tion about the Screen section, and they may also be included
here.
ServerLayout sections have the following format:
Section "ServerLayout"
Identifier "name"
Screen "screen-id"
...
InputDevice "idev-id"
...
options
...
EndSection
Each ServerLayout section must have an Identifier entry and at least
one Screen entry.
The Identifier entry specifies the unique name for this server layout.
The ServerLayout section provides information specific to the whole
session, including session-specific Options. The ServerFlags options
(described above) may be specified here, and ones given here override
those given in the ServerFlags section.
The entries that may be used in this section are described here.
Screen screen-num "screen-id" position-information
One of these entries must be given for each screen being used in
a session. The screen-id field is mandatory, and specifies the
Screen section being referenced. The screen-num field is
optional, and may be used to specify the screen number in multi-
head configurations. When this field is omitted, the screens
will be numbered in the order that they are listed in. The num-
bering starts from 0, and must be consecutive. The position-
information field describes the way multiple screens are posi-
tioned. There are a number of different ways that this informa-
tion can be provided:
x y
Absolute x y
These both specify that the upper left corner's coordinates
are (x,y). The Absolute keyword is optional. Some older
versions of Xorg (4.2 and earlier) don't recognise the Abso-
lute keyword, so it's safest to just specify the coordinates
without it.
RightOf "screen-id"
LeftOf "screen-id"
Above "screen-id"
Below "screen-id"
for the core pointer and keyboard devices. If either of those
is missing, suitable InputDevice entries are searched for using
the method described above in the INPUTDEVICE section. The
idev-id field is mandatory, and specifies the name of the Input-
Device section being referenced. Multiple option fields may be
specified, each in double quotes. The options permitted here
are any that may also be given in the InputDevice sections.
Normally only session-specific input device options would be
used here. The most commonly used options are:
"CorePointer"
"CoreKeyboard"
"SendCoreEvents"
and the first two should normally be used to indicate the core
pointer and core keyboard devices respectively.
Options
Any option permitted in the ServerFlags section may also be
specified here. When the same option appears in both places,
the value given here overrides the one given in the ServerFlags
section.
Here is an example of a ServerLayout section for a dual headed configu-
ration with two mice:
Section "ServerLayout"
Identifier "Layout 1"
Screen "MGA 1"
Screen "MGA 2" RightOf "MGA 1"
InputDevice "Keyboard 1" "CoreKeyboard"
InputDevice "Mouse 1" "CorePointer"
InputDevice "Mouse 2" "SendCoreEvents"
Option "BlankTime" "5"
EndSection
DRI SECTION
This optional section is used to provide some information for the
Direct Rendering Infrastructure. Details about the format of this sec-
tion can be found in the README.DRI document, which is also available
on-line at <http://www.x.org>.
VENDOR SECTION
The optional Vendor section may be used to provide vendor-specific con-
figuration information. Multiple Vendor sections may be present, and
they may contain an Identifier entry and multiple Option flags. The
data therein is not used in this release.
FILES
For an example of an xorg.conf file, see the file installed as
/usr/X11R6/lib/X11/xorg.conf.eg.
X.Org Version 6.8.2 xorg.conf(4)
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