Xorg - X11R7 X server
Xorg [:display] [option ...]
Xorg is a full featured X server that was originally designed for UNIX and UNIX-like oper-
ating systems running on Intel x86 hardware. It now runs on a wider range of hardware and
This work was derived by the X.Org Foundation from the XFree86 Project's XFree86 4.4rc2
release. The XFree86 release was originally derived from X386 1.2 by Thomas Roell which
was contributed to X11R5 by Snitily Graphics Consulting Service.
Xorg operates under a wide range of operating systems and hardware platforms. The Intel
x86 (IA32) architecture is the most widely supported hardware platform. Other hardware
platforms include Compaq Alpha, Intel IA64, AMD64, SPARC and PowerPC. The most widely
supported operating systems are the free/OpenSource UNIX-like systems such as Linux, Free-
BSD, NetBSD, OpenBSD, and Solaris. Commercial UNIX operating systems such as UnixWare are
also supported. Other supported operating systems include GNU Hurd. Mac OS X is sup-
ported with the Xquartz(1) X server. Win32/Cygwin is supported with the XWin(1) X server.
Xorg supports connections made using the following reliable byte-streams:
On most platforms, the "Local" connection type is a UNIX-domain socket. On some Sys-
tem V platforms, the "local" connection types also include STREAMS pipes, named pipes,
and some other mechanisms.
Xorg listens on port 6000+n, where n is the display number. This connection type can
be disabled with the -nolisten option (see the Xserver(1) man page for details).
For operating systems that support local connections other than Unix Domain sockets (SVR3
and SVR4), there is a compiled-in list specifying the order in which local connections
should be attempted. This list can be overridden by the XLOCAL environment variable
described below. If the display name indicates a best-choice connection should be made
(e.g. :0.0), each connection mechanism is tried until a connection succeeds or no more
mechanisms are available. Note: for these OSs, the Unix Domain socket connection is
treated differently from the other local connection types. To use it the connection must
be made to unix:0.0.
The XLOCAL environment variable should contain a list of one more more of the following:
which represent SVR4 Named Streams pipe, Old-style USL Streams pipe, SCO XSight Streams
pipe, and ISC Streams pipe, respectively. You can select a single mechanism (e.g. XLO-
CAL=NAMED), or an ordered list (e.g. XLOCAL="NAMED:PTS:SCO"). his variable overrides the
compiled-in defaults. For SVR4 it is recommended that NAMED be the first preference con-
nection. The default setting is PTS:NAMED:ISC:SCO.
To globally override the compiled-in defaults, you should define (and export if using sh
or ksh) XLOCAL globally. If you use startx(1) or xinit(1), the definition should be at
the top of your .xinitrc file. If you use xdm(1), the definitions should be early on in
the /usr/lib/X11/xdm/Xsession script.
Xorg supports several mechanisms for supplying/obtaining configuration and run-time param-
eters: command line options, environment variables, the xorg.conf(5) configuration files,
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 parameters can be supplied via all meth-
ods. The available command line options and environment variables (and some defaults) are
described here and in the Xserver(1) manual page. Most configuration file parameters,
with their defaults, are described in the xorg.conf(5) manual page. Driver and module
specific configuration parameters are described in the relevant driver or module manual
In addition to the normal server options described in the Xserver(1) manual page, Xorg
accepts the following command line switches:
vtXX XX specifies the Virtual Terminal device number which Xorg will use. Without this
option, Xorg will pick the first available Virtual Terminal that it can locate.
This option applies only to platforms that have virtual terminal support, such as
Linux, BSD, OpenSolaris, SVR3, and SVR4.
Allow the server to start up even if the mouse device can't be opened or ini-
tialised. This is equivalent to the AllowMouseOpenFail xorg.conf(5) file option.
Make the VidMode extension available to remote clients. This allows the xvidtune
client to connect from another host. This is equivalent to the AllowNonLocalXvid-
tune xorg.conf(5) file option. By default non-local connections are not allowed.
Set the blue gamma correction. value must be between 0.1 and 10. The default is
1.0. Not all drivers support this. See also the -gamma, -rgamma, and -ggamma
-bpp n No longer supported. Use -depth to set the color depth, and use -fbbpp if you
really need to force a non-default framebuffer (hardware) pixel format.
Read the server configuration from file. This option will work for any file when
the server is run as root (i.e, with real-uid 0), or for files relative to a
directory in the config search path for all other users.
Read the server configuration files from directory. This option will work for any
directory when the server is run as root (i.e, with real-uid 0), or for directo-
ries relative to a directory in the config directory search path for all other
When this option is specified, the Xorg server loads all video driver modules,
probes for available hardware, and writes out an initial xorg.conf(5) file based
on what was detected. This option currently has some problems on some platforms,
but in most cases it is a good way to bootstrap the configuration process. This
option is only available when the server is run as root (i.e, with real-uid 0).
SCO only. This is the same as the vt option, and is provided for compatibility
with the native SCO X server.
Sets the default color depth. Legal values are 1, 4, 8, 15, 16, and 24. Not all
drivers support all values.
Disable the parts of the VidMode extension (used by the xvidtune client) that can
be used to change the video modes. This is equivalent to the DisableVidModeExten-
sion xorg.conf(5) file option.
Sets the number of framebuffer bits per pixel. You should only set this if you're
sure it's necessary; normally the server can deduce the correct value from -depth
above. Useful if you want to run a depth 24 configuration with a 24 bpp frame-
buffer rather than the (possibly default) 32 bpp framebuffer (or vice versa).
Legal values are 1, 8, 16, 24, 32. Not all drivers support all values.
Swap the default values for the black and white pixels.
Set the gamma correction. value must be between 0.1 and 10. The default is 1.0.
This value is applied equally to the R, G and B values. Those values can be set
independently with the -rgamma, -bgamma, and -ggamma options. Not all drivers
Set the green gamma correction. value must be between 0.1 and 10. The default is
1.0. Not all drivers support this. See also the -gamma, -rgamma, and -bgamma
The Xorg server checks the ABI revision levels of each module that it loads. It
will normally refuse to load modules with ABI revisions that are newer than the
server's. This is because such modules might use interfaces that the server does
not have. When this option is specified, mismatches like this are downgraded from
fatal errors to warnings. This option should be used with care.
Restrict device resets to the device at bus-id. The bus-id string has the form
bustype:bus:device:function (e.g., 'PCI:1:0:0'). At present, only isolation of
PCI devices is supported; i.e., this option is ignored if bustype is anything
other than 'PCI'.
Prevent the server from detaching its initial controlling terminal. This option
is only useful when debugging the server. Not all platforms support (or can use)
Use the xorg.conf(5) file InputDevice section called keyboard-name as the core
keyboard. This option is ignored when the Layout section specifies a core key-
board. In the absence of both a Layout section and this option, the first rele-
vant InputDevice section is used for the core keyboard.
Use the xorg.conf(5) file Layout section called layout-name. By default the first
Layout section is used.
Use the file called filename as the Xorg server log file. The default log file is
/var/log/Xorg.n.log on most platforms, where n is the display number of the Xorg
server. The default may be in a different directory on some platforms. This
option is only available when the server is run as root (i.e, with real-uid 0).
Sets the verbosity level for information printed to the Xorg server log file. If
the n value isn't supplied, each occurrence of this option increments the log file
verbosity level. When the n value is supplied, the log file verbosity level is
set to that value. The default log file verbosity level is 3.
Set the module search path to searchpath. searchpath is a comma separated list of
directories to search for Xorg server modules. This option is only available when
the server is run as root (i.e, with real-uid 0).
-nosilk Disable Silken Mouse support.
Disable the automatic switching on X server reset and shutdown to the VT that was
active when the server started, if supported by the OS.
Set the internal pixmap format for depth 24 pixmaps to 24 bits per pixel. The
default is usually 32 bits per pixel. There is normally little reason to use this
option. Some client applications don't like this pixmap format, even though it is
a perfectly legal format. This is equivalent to the Pixmap xorg.conf(5) file
Set the internal pixmap format for depth 24 pixmaps to 32 bits per pixel. This is
usually the default. This is equivalent to the Pixmap xorg.conf(5) file option.
Use the xorg.conf(5) file InputDevice section called pointer-name as the core
pointer. This option is ignored when the Layout section specifies a core pointer.
In the absence of both a Layout section and this option, the first relevant Input-
Device section is used for the core pointer.
-quiet Suppress most informational messages at startup. The verbosity level is set to
Set the red gamma correction. value must be between 0.1 and 10. The default is
1.0. Not all drivers support this. See also the -gamma, -bgamma, and -ggamma
Share virtual terminals with another X server, if supported by the OS.
Use the xorg.conf(5) file Screen section called screen-name. By default the
screens referenced by the default Layout section are used, or the first Screen
section when there are no Layout sections.
This is the same as the -version option, and is included for compatibility rea-
sons. It may be removed in a future release, so the -version option should be
Print out the default module path the server was compiled with.
Print out the path libraries should be installed to.
For each driver module installed, print out the list of options and their argument
Set RGB weighting at 16 bpp. The default is 565. This applies only to those
drivers which support 16 bpp.
Sets the verbosity level for information printed on stderr. If the n value isn't
supplied, each occurrence of this option increments the verbosity level. When the
n value is supplied, the verbosity level is set to that value. The default ver-
bosity level is 0.
Print out the server version, patchlevel, release date, the operating system/plat-
form it was built on, and whether it includes module loader support.
The Xorg server is normally configured to recognize various special combinations of key
presses that instruct the server to perform some action, rather than just sending the key
press event to a client application. These actions depend on the XKB keymap loaded by a
particular keyboard device and may or may not be available on a given configuration.
The following key combinations are commonly part of the default XKEYBOARD keymap.
Immediately kills the server -- no questions asked. It can be disabled by setting
the DontZap xorg.conf(5) file option to a TRUE value.
It should be noted that zapping is triggered by the Terminate_Server action in the
keyboard map. This action is not part of the default keymaps but can be enabled
with the XKB option "terminate:ctrl_alt_bksp".
Change video mode to next one specified in the configuration file. This can be
disabled with the DontZoom xorg.conf(5) file option.
Change video mode to previous one specified in the configuration file. This can
be disabled with the DontZoom xorg.conf(5) file option.
For systems with virtual terminal support, these keystroke combinations are used
to switch to virtual terminals 1 through 12, respectively. This can be disabled
with the DontVTSwitch xorg.conf(5) file option.
Xorg typically uses a configuration file called xorg.conf and configuration files with the
suffix .conf in a directory called xorg.conf.d for its initial setup. Refer to the
xorg.conf(5) manual page for information about the format of this file.
Xorg has a mechanism for automatically generating a built-in configuration at run-time
when no xorg.conf file or xorg.conf.d files are present. The current version of this
automatic configuration mechanism works in two ways.
The first is via enhancements that have made many components of the xorg.conf file
optional. This means that information that can be probed or reasonably deduced doesn't
need to be specified explicitly, greatly reducing the amount of built-in configuration
information that needs to be generated at run-time.
The second is to have "safe" fallbacks for most configuration information. This maximises
the likelihood that the Xorg server will start up in some usable configuration even when
information about the specific hardware is not available.
The automatic configuration support for Xorg is work in progress. It is currently aimed
at the most popular hardware and software platforms supported by Xorg. Enhancements are
planned for future releases.
The Xorg server config files can be found in a range of locations. These are documented
fully in the xorg.conf(5) manual page. The most commonly used locations are shown here.
/etc/X11/xorg.conf Server configuration file.
/etc/X11/xorg.conf-4 Server configuration file.
/etc/xorg.conf Server configuration file.
/usr/etc/xorg.conf Server configuration file.
/usr/lib/X11/xorg.conf Server configuration file.
/etc/X11/xorg.conf.d Server configuration directory.
/etc/X11/xorg.conf.d-4 Server configuration directory.
/etc/xorg.conf.d Server configuration directory.
/usr/etc/xorg.conf.d Server configuration directory.
/usr/lib/X11/xorg.conf.d Server configuration directory.
/var/log/Xorg.n.log Server log file for display n.
/usr/bin/* Client binaries.
/usr/include/* Header files.
/usr/share/X11/XErrorDB Client error message database.
/usr/lib/X11/app-defaults/* Client resource specifications.
/usr/share/man/man?/* Manual pages.
/etc/Xn.hosts Initial access control list for display n.
X(7), Xserver(1), xdm(1), xinit(1), xorg.conf(5), xvidtune(1), xkeyboard-config (7),
apm(4), ati(4), chips(4), cirrus(4), cyrix(4), fbdev(4), glide(4), glint(4), i128(4),
i740(4), imstt(4), intel(4), mga(4), neomagic(4), nsc(4), nv(4), openchrome (4), r128(4),
rendition(4), s3virge(4), siliconmotion(4), sis(4), sunbw2(4), suncg14(4), suncg3(4),
suncg6(4), sunffb(4), sunleo(4), suntcx(4), tdfx(4), tga(4), trident(4), tseng(4), v4l(4),
Web site <http://www.x.org>.
Xorg has many contributors world wide. The names of most of them can be found in the doc-
umentation, ChangeLog files in the source tree, and in the actual source code.
Xorg was originally based on XFree86 4.4rc2. That was originally based on X386 1.2 by
Thomas Roell, which was contributed to the then X Consortium's X11R5 distribution by SGCS.
Xorg is released by the X.Org Foundation.
The project that became XFree86 was originally founded in 1992 by David Dawes, Glenn Lai,
Jim Tsillas and David Wexelblat.
XFree86 was later integrated in the then X Consortium's X11R6 release by a group of dedi-
cated XFree86 developers, including the following:
Stuart Anderson email@example.com
Doug Anson firstname.lastname@example.org
Gertjan Akkerman email@example.com
Mike Bernson firstname.lastname@example.org
Robin Cutshaw robin@XFree86.org
David Dawes dawes@XFree86.org
Marc Evans marc@XFree86.org
Pascal Haible email@example.com
Matthieu Herrb Matthieu.Herrb@laas.fr
Dirk Hohndel hohndel@XFree86.org
David Holland firstname.lastname@example.org
Alan Hourihane email@example.com
Jeffrey Hsu firstname.lastname@example.org
Glenn Lai email@example.com
Ted Lemon firstname.lastname@example.org
Rich Murphey rich@XFree86.org
Hans Nasten email@example.com
Mark Snitily firstname.lastname@example.org
Randy Terbush email@example.com
Jon Tombs tombs@XFree86.org
Kees Verstoep firstname.lastname@example.org
Paul Vixie email@example.com
Mark Weaver Mark_Weaver@brown.edu
David Wexelblat dwex@XFree86.org
Philip Wheatley Philip.Wheatley@ColumbiaSC.NCR.COM
Thomas Wolfram firstname.lastname@example.org
Orest Zborowski email@example.com
Xorg source is available from the FTP server <ftp://ftp.x.org/>, and from the X.Org server
<http://gitweb.freedesktop.org/>. Documentation and other information can be found from
the X.Org web site <http://www.x.org/>.
Xorg is copyright software, provided under licenses that permit modification and redistri-
bution in source and binary form without fee. Xorg is copyright by numerous authors and
contributors from around the world. Licensing information can be found at
<http://www.x.org>. Refer to the source code for specific copyright notices.
XFree86(TM) is a trademark of The XFree86 Project, Inc.
X11(TM) and X Window System(TM) are trademarks of The Open Group.
X Version 11 xorg-server 1.15.0 Xorg(1)