View source for X.Org Server

{{short description|Free and open-source display server for X Window System}}
{{Distinguish|X.Org Foundation}}
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{{More citations needed|date=July 2017}}
{{Primary sources|date=July 2017}}
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{{Use dmy dates|date=August 2015}}
{{Infobox software
| title                  = X.Org Server
| name                   = X.Org Server
| logo                   = X.Org Logo.svg{{!}}class=skin-invert
| logo upright           = 0.4
| logo alt               = X.Org Server logo
| logo caption           =
| screenshot             = <!-- Image name is enough -->
| screenshot size        =
| screenshot alt         =
| caption                =
| collapsible            =
| author                 =
| developer              = [[X.Org Foundation]]
| released               = {{Start date and age|df=yes|2004|04|06}}<ref name="announceX11R6.7">{{cite web
 | url        = https://lwn.net/Articles/79302/
 | title      = X.Org Foundation releases X Window System X11R6.7
 | date       = 7 April 2004
 | access-date = 2012-04-04
 | publisher  = [[LWN.net]]}}</ref>
| latest release version = {{wikidata|property|preferred|references|edit|Q518900|P348|P548=Q2804309}}
| latest release date    = {{wikidata|qualifier|preferred|single|Q518900|P348|P548=Q2804309|P577}}
| latest preview version = {{wikidata|property|preferred|references|edit|Q518900|P348|P548=Q51930650}}
| latest preview date    = {{wikidata|qualifier|preferred|single|Q518900|P348|P548=Q51930650|P577}}
| programming language   = [[C (programming language)|C]]
| operating system       = [[Cross-platform]]
| platform               =
| size                   = 3.7&nbsp;MiB<ref>{{cite web
 | url   = http://packages.debian.org/sid/xserver-xorg-core
 | title = Debian X.Org Server Package in sid}}</ref>
| language               = [[English Language|English]]
| language count         = <!-- Number only -->
| language footnote      =
| genre                  = [[Display server]]
| license                = [[MIT License]]
| alexa                  =
| website                = {{URL|https://x.org}}
| standard               =
}}

'''X.Org Server''' is the [[Free and open-source software|free and open-source]] implementation of the [[X Window System]] (X11) [[display server]] stewarded by the [[X.Org Foundation]].

Implementations of the client-side [[X Window System]] protocol exist in the form of ''X11 libraries'', which serve as helpful APIs for communicating with the X server.<ref>{{cite web|url=https://www.x.org/wiki/guide/xlib-and-xcb/#:~:text=At,server.|title=Xlib and XCB}}</ref> Two such major X libraries exist for X11. The first of these libraries was [[Xlib]], the original C language X11 API,<ref>{{cite web|url=https://www.x.org/wiki/guide/xlib-and-xcb/#:~:text=The%20original,%22Xlib%22.|title=Xlib and XCB}}</ref> but another C language X library, [[XCB]], was created later in 2001.<ref>{{cite web|url=https://www.x.org/wiki/guide/xlib-and-xcb/#:~:text=After%20many,XCB.|title=Xlib and XCB}}</ref> Other smaller X libraries exist, both as interfaces for [[Xlib]] and [[XCB]] in other languages, and as smaller standalone X libraries.{{citation needed|date=August 2022}}

The services with which the X.Org Foundation supports X Server include the packaging of the releases; certification (for a fee); evaluation of improvements to the code; developing the web site, and handling the distribution of monetary donations.{{citation needed|date=September 2011}} The releases are coded, documented, and packaged by global [[developer (software)|developer]]s.{{clarify|what is a global developer?|date=January 2012}}

==Software architecture==
[[File:Xdpyinfo screenshot.png|upright=1.5|thumb|<code>xdpyinfo</code>, a command to show X.Org Server information]]
The X.Org Server implements the server side of the [[X Window System core protocol]] version 11 (X11) and extensions to it, e.g. RandR.<ref>{{cite web |url=http://cgit.freedesktop.org/xorg/xserver/tree/randr |title=git: xorg-server, RandR}}</ref>

Version 1.16.0 integrates support for [[systemd]]-based launching and management which improved boot performance and reliability.<ref name="xorgserver1160" />

==={{Anchor|DIX}} Device Independent X (DIX)===
The Device Independent X (DIX) is the part of the X.Org Server that interacts with clients and implements software rendering. The main loop and the event delivery are part of the DIX.<ref>{{Cite web|url=https://www.x.org/wiki/Development/Documentation/Glossary/|title=Glossary|website=X.org}}</ref>

An X server has a tremendous amount of functionality that must be implemented to support the X core protocol. This includes code tables, glyph rasterization and caching, [[X logical font description|XLFDs]], and the core rendering API which draws graphics primitives.

==={{Anchor|DDX}} Device Dependent X (DDX)===
The Device Dependent X (DDX) is the part of the x-server that interacts with the hardware. In the X.Org Server source code, each directory under "hw" corresponds to one DDX. Hardware comprises graphics cards as well as mouse and keyboards. Each driver is hardware specific and implemented as a separate loadable module.

===={{Anchor|DDX graphics driver}} 2D graphics driver====
For historical reasons the X.Org Server still contains graphics device drivers supporting some form of 2D rendering acceleration. In the past, [[mode-setting]] was done by an X-server graphics device driver specific to some [[video controller]] hardware (''e.g.'', a [[Graphics processing unit|GPU]]). To this mode-setting functionality, additional support for 2D acceleration was added when such became available with various GPUs. The mode-setting functionality was moved into the [[Direct Rendering Manager|DRM]] and is being exposed through a DRM mode-setting interface, the new approach being called "kernel mode-setting" (KMS). But the 2D rendering acceleration remained.

In [[Debian]] the 2D graphics drivers for the X.Org Server are packaged individually and called ''xserver-xorg-video-*''.<ref>{{Cite web|url=https://packages.debian.org/stretch/xserver-xorg-video-nouveau|title=Details of package xserver-xorg-video-nouveau in stretch|website=packages.debian.org}}</ref> After installation the 2D graphics driver-file is found under <code>/usr/lib/xorg/modules/drivers/</code>. The package xserver-xorg-video-nouveau installs <code>nouveau_drv.so</code> with a size of 215 KiB, the proprietary [[Nvidia GeForce driver]] installs an 8 MiB-sized file called <code>nvidia_drv.so</code> and [[Radeon Software]] installs <code>fglrx_drv.so</code> with a size of about 25MiB.

The available [[free and open-source graphics device driver]]s are being developed inside of the [[Mesa 3D]]-project. While these can be recompiled as required, the development of the proprietary DDX 2D graphics drivers is greatly eased when the X.Org Server keeps a stable API/ABI across multiple of its versions.

With version 1.17 a generic method for mode-setting was mainlined. The <code>xf86-video-modesetting</code> package, the Debian-package being called <code>xserver-xorg-video-modesetting</code>, was retired, and the generic modesetting DDX it contained was moved into the server package to become the KMS-enabled default DDX, supporting the vast majority of AMD, Intel and NVidia GPUs.

On April 7, 2016, AMD employee Michel Dänzer released <code>xf86-video-ati</code> version 7.7.0<ref>{{cite web |url=https://lists.x.org/archives/xorg-announce/2016-April/002684.html |title=[ANNOUNCE] xf86-video-ati 7.7.0 |date=2016-04-07}}</ref> and <code>xf86-video-amdgpu</code> version 1.1.0,<ref>{{cite web |url=https://lists.x.org/archives/xorg-announce/2016-April/002686.html |title=[ANNOUNCE] xf86-video-amdgpu 1.1.0 |date=2016-04-07}}</ref> the latter including support for their [[Polaris (microarchitecture)|Polaris]] microarchitecture.

====={{Anchor|Acceleration-anchor}} Acceleration architectures=====
There are (at least) XAA (XFree86 Acceleration Architecture),<ref name="StupidSquirrel">{{cite web|url=http://www.xfree86.org/3.3.6/ark3.html|title=Information for ARK Logic Chipset Users: Acceleration|website=XFree86.org|access-date=22 September 2018|url-status=live|archive-url=https://web.archive.org/web/20180623033423/http://www.xfree86.org/3.3.6/ark3.html|archive-date=23 June 2018}}</ref> [[EXA]], [[UMA Acceleration Architecture|UXA]] and [[SNA (computer graphics)|SNA]].

[[File:Linux graphics drivers 2D.svg|upright=1.5|thumb|'''XAA''' is an API between the Device-Independent-X (DIX) and the Device-Dependent-X (DDX), a 2D graphics driver, here e.g. with the [[Linux kernel]].]]
In the [[X Window System]], '''XFree86 Acceleration Architecture''' ('''XAA''') is a driver architecture to make a video card's 2D [[hardware acceleration]] available to the X server.<ref name="anholt2004">{{cite web |last1=Anholt |first1=Eric |title=High Performance X Servers in the Kdrive Architecture |url=https://www.usenix.org/legacy/event/usenix04/tech/freenix/full_papers/anholt/anholt_html/ |website=www.usenix.org |access-date=14 September 2018}}</ref><ref name="Wetzel2003">{{cite web |last1=Wetzel |first1=Robert |title=An acceleration architecture for DOpE |url=http://wwwos.inf.tu-dresden.de/papers_ps/wetzel-diplom.pdf |website=wwwos.inf.tu-dresden.de |access-date=14 September 2018}}</ref> It was written by [[Harm Hanemaayer]] in 1996 and first released in [[XFree86]] version 3.3. It was completely rewritten for XFree86 4.0.<ref>{{cite web|title=Release Notes for XFree86 4.0|url=http://www.xfree86.org/4.0/RELNOTES2.html#6|website=XFree86 Project|date=7 March 2000|access-date=16 September 2018}}</ref> It was removed again from X.Org Server 1.13.

Most drivers implement acceleration using the XAA module. XAA is on by default, though acceleration of individual functions can be switched off as needed in the server configuration file (<code>XF86Config</code> or <code>xorg.conf</code>).

The driver for the [[ARK chipset]] was the original development platform for XAA.

In X.Org Server release 6.9/7.0, [[EXA]] was released as a replacement for XAA, as XAA supplies almost no speed advantage for current video cards. EXA is regarded as an intermediate step to converting the entire X server to using [[OpenGL]].

====={{Anchor|GLAMOR}} Glamor=====
Glamor is a generic, hardware independent, 2D acceleration driver for the X server that translates the X render primitives into [[OpenGL]] operations, taking advantage of any existing 3D OpenGL drivers.<ref>{{cite web|title=What is Glamor?|url=http://www.freedesktop.org/wiki/Software/Glamor/|publisher=FreeDesktop.org|access-date=10 February 2014}}</ref> In this way, it is functionally similar to Quartz Extreme and QuartzGL (2D performance acceleration) for Apple [[Quartz Compositor]].

The ultimate goal of GLAMOR is to obsolete and replace all the DDX 2D graphics device drivers and acceleration architectures, thereby avoiding the need to write X 2D specific drivers for every supported graphic chipset.<ref>{{cite web|last=Anholt|first=Eric|title=Building 2D rendering acceleration with OpenGL|url=http://mirror.linux.org.au/linux.conf.au/2014/Wednesday/52-Building_2D_rendering_acceleration_with_OpenGL_-_Eric_Anholt.mp4|publisher=[[linux.conf.au]]|access-date=10 February 2014|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304064444/http://mirror.linux.org.au/linux.conf.au/2014/Wednesday/52-Building_2D_rendering_acceleration_with_OpenGL_-_Eric_Anholt.mp4|url-status=dead}}</ref><ref>{{cite web|last=Packard|first=Keith|title=Brief Glamor Hacks|url=http://keithp.com/blogs/glamor-hacking/|access-date=7 March 2014}}</ref><ref>{{cite web |url=http://wiki.x.org/wiki/Events/XDC2013/XDC2013AdamJacksonGLXRewrite/ |title=Adam Jackson – GLX rewrite |date=24 September 2013 |access-date=2014-03-23}}</ref> Glamor requires a 3D driver with support for [[shader]]s.<ref>{{cite web |url=http://xorg.freedesktop.org/wiki/RadeonFeature/ |title=Radeon Feature Matrix |work=[[freedesktop.org]]}}</ref>

Glamor performance tuning was accepted for [[Google Summer of Code]] 2014.<ref>{{Cite web|url=http://www.google-melange.com/gsoc/project/details/google/gsoc2014/degasus/5639274879778816|title=Glamor Performance Tuning|access-date=22 April 2014|archive-date=24 September 2015|archive-url=https://web.archive.org/web/20150924023047/http://www.google-melange.com/gsoc/project/details/google/gsoc2014/degasus/5639274879778816|url-status=dead}}</ref> Glamor supports [[Xephyr]] and [[Direct Rendering Infrastructure#DRI3|DRI3]],<ref>{{cite web |url=https://www.phoronix.com/scan.php?page=news_item&px=MTYyMjc |title=GLAMOR Xephyr & DRI3 Support Called For Pulling |publisher=[[Phoronix]] |date=5 March 2014}}</ref> and can boost some operations by 700–800%.<ref>{{cite web |url=https://www.phoronix.com/scan.php?page=news_item&px=MTYyODU |title=GLAMOR Patch Bomb Can Boost Some Operations By 700~800% |publisher=[[Phoronix]] |date=13 March 2014}}</ref> Since its mainlining into version 1.16 of the X.Org Server, development on Glamor was continued and patches for the 1.17 release were published.<ref>{{cite web |url=http://lists.x.org/archives/xorg-devel/2014-July/043106.html |title=glamor changes for 1.17 |date=17 July 2014}}</ref>

====={{Anchor|Virtualization}} Virtualization=====
There is a distinct and special DDX for instances of the X.Org Server which run on a guest system inside of a [[Virtualization|virtualized environment]]: xf86-video-qxl, a driver for the "QXL video device". [[Simple Protocol for Independent Computing Environments|SPICE]] makes use of this driver though it works without it as well.

In the Debian repositories it is called xserver-xorg-video-qxl, cf. https://packages.debian.org/buster/xserver-xorg-video-qxl

===={{Anchor|Input stack}} Input stack====
Under Debian, drivers related to input are found under <code>/usr/lib/xorg/modules/input/</code>. Such drivers are named e.g. <code>evdev_drv.so</code>, <code>mouse_drv.so</code>, <code>synaptics_drv.so</code> or <code>wacom_drv.so</code>.

With version 1.16, the X.Org Server obtained support for the [[libinput]] library in form of a wrapper called <code>xf86-input-libinput</code>.<ref>{{Cite web|url=http://who-t.blogspot.com/2014/09/libinput-common-input-stack-for-wayland.html|title=libinput – a common input stack for Wayland compositors and X.Org drivers|first=Peter|last=Hutterer|date=24 September 2014}}</ref> At the XDC 2015 in Toronto, libratbag was introduced as a generic library to support configurable mice.<ref>{{Cite web|url=https://www.x.org/wiki/Events/XDC2015/Program/hutterer_tissoires_libratbag.html|title=libratbag|website=X.org}}</ref><ref>{{Cite web|url=https://www.x.org/wiki/Events/XDC2015/Program/tissoires_input_debug_tools.html|title=Tools to debug a broken input device|website=X.org}}</ref> <code>xserver-xorg-input-joystick</code> is the input module for the X.Org server to handle classic joysticks and gamepads, which is not meant for playing games under X, but to control the cursor with a joystick or gamepad.<ref>{{cite web |url=http://www.x.org/wiki/Events/XDC2012/XDC2012AbstractSaschaHlusiak/xf86-input-joystick.pdf |title=XDC2012: xorg-input-joystick |type=pdf}}</ref><ref>{{Cite web|url=https://packages.debian.org/stable/xserver-xorg-input-joystick|title= Details of package xserver-xorg-input-joystick in buster|website=packages.debian.org}}</ref>

====Other DDX components====
; {{Anchor|XWayland}} XWayland
: XWayland is a series of patches over the X.Org server codebase that implement an X server running upon the [[Wayland (protocol)|Wayland]] protocol. The patches are developed and maintained by the Wayland developers for compatibility with X11 applications during the transition to Wayland,<ref>{{cite web|title=X Clients under Wayland (XWayland)|url=http://wayland.freedesktop.org/xserver.html|publisher=Wayland Project|access-date=10 February 2014|archive-date=9 February 2014|archive-url=https://web.archive.org/web/20140209191246/http://wayland.freedesktop.org/xserver.html|url-status=dead}}</ref> and were mainlined in version 1.16 of the X.Org Server in 2014.<ref name="xorgserver1160">{{cite web |url=http://lists.x.org/archives/xorg-announce/2014-July/002457.html |title=ANNOUNCE: xorg-server 1.16.0 |publisher=[[freedesktop.org]] |date=17 July 2014}}</ref> When a user runs an X application from within [[Weston (software)|Weston]], it calls upon XWayland to service the request.<ref>
{{cite web|title=Wayland|url=https://wiki.archlinux.org/index.php/wayland#XWayland|publisher=[[Arch Linux]] Project|access-date=2016-05-09}}</ref>
; {{Anchor|XQuartz}} XQuartz
: XQuartz is a series of patches from [[Apple Inc.]] to integrate support for the X11 protocol into their [[Quartz Compositor]], in a similar way to how XWayland integrates X11 into [[Wayland compositor]]s.
; Xspice
: Xspice is a device driver for the X.Org Server. It supports the QXL framebuffer device and includes a wrapper script<ref>{{cite web|url=http://cgit.freedesktop.org/xorg/driver/xf86-video-qxl/tree/README.xspice |title=XSpice README |publisher=Cgit.freedesktop.org |access-date=2013-10-25}}</ref> which makes it possible to launch an X.Org Server whose display is exported via the [[SPICE (protocol)|SPICE]] protocol. This enables use of SPICE in a remote desktop environment, without requiring [[Kernel-based Virtual Machine|KVM]] virtualization.
; Xephyr
: [[Xephyr]] is an X-on-X implementation. Since version 1.16.0, Xephyr serves as the primary development environment for the new 2D acceleration subsystem (Glamor), permitting rapid development and testing on a single machine.<ref name="xorgserver1160" />
; RandR
: '''RandR''' (''resize and rotate'') is a [[communications protocol]] written as an extension to the [[X Window System core protocol|X11]]<ref>{{cite web|url=http://cgit.freedesktop.org/xorg/proto/randrproto/tree/randrproto.txt|title=The X Resize, Rotate and Reflect Extension Version 1.3.1}}</ref> protocol. XRandR provides the ability to resize, rotate and reflect the [[root window]] of a screen. RandR is responsible for setting the screen refresh rate.<ref name="Tyler2008">{{cite book |last1=Tyler |first1=Chris |title=X Power Tools |date=2008 |publisher="O'Reilly Media, Inc." |isbn=9780596101954 |pages=86–87 |url=https://books.google.com/books?id=X9YRMIA899gC&q=%22XRandR%22+-wikipedia&pg=PA87 |access-date=14 September 2018 |language=en}}</ref> It allows for the control of multiple monitors.<ref name="Gultsch2009">{{cite journal |last1=Gultsch |first1=Daniel |title=Dual Image » Linux Magazine |journal=Linux Magazine |date=2009 |issue=106 |url=http://www.linux-magazine.com/Issues/2009/106/Multi-heading-with-RandR}}</ref>

===IPC===
The X.Org Server, and any x-client, each run as distinct processes. On Unix/Linux, a process knows nothing about any other processes. For it to communicate with another process, it is completely and utterly reliant on the kernel to moderate the communication via available [[inter-process communication]] (IPC) mechanisms.
[[Unix domain socket]]s are used to communicate with processes running on the same machine. Special socket function calls are part of the System Call Interface. Although [[Network socket|Internet domain sockets]] can be used locally, Unix domain sockets are more efficient, since they do not have the [[Communications protocol|protocol]] overhead ([[checksum]]s, byte orders, etc.).

X.Org Server does not use [[D-Bus]].

Sockets are the most common interprocess communication (IPC) method between the processes of the X server and its various X clients. It provides the Application Programming Interface (API) for communication in the TCP/IP domain and also locally only in the UNIX domain. There are several other APIs described in the X Transport Interface, for instance TLI (Transport Layer Interface). Other options for IPC between for the X client-server, require X Window system extensions, for instance the [[MIT-SHM|MIT Shared Memory Extension (MIT-SHM)]].

===Multiseat configuration===
Multi-seat refers to an assembly of a single computer with multiple "seats", allowing multiple users to sit down at the computer, log in, and use the computer at the same time independently. The computer has multiple keyboards, mice, and monitors attached to it, each "seat" having one keyboard, one mouse and one monitor assigned to it. A "seat" consists of all hardware devices assigned to a specific workplace. It consists of at least one graphics device (graphics card or just an output and the attached monitor) and a keyboard and a mouse. It can also include video cameras, sound cards and more.

Due to limitation of the VT system in the Linux kernel and of the X core protocol (in particular, how X defines the relation between the root window and an output of the graphics card), multi-seat does not work out-of-the-box for the usual Linux distribution but necessitates a special configuration.

There are these methods to configure a multi-seat assembly:
* multiple [[Xephyr]] servers over a host xorg-server
* multiple instances of an xorg-server
** one graphics card per seat
** a single graphics card for all seats

The utilized command-line options of the xorg-server are:
* <code>-isolateDevice bus-id</code> Restrict device resets (output) 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'.
* <code>vtXX</code> the default for e.g. Debian 9 Stretch is 7, i.e. by pressing {{Key|Ctrl}}+{{Key|Alt}}+{{Key|F7}} the user can switch to the VT running the xorg-server.

Only the user on the first monitor has the use of vt consoles and can use {{Key|Ctrl}}+{{Key|Alt}}+{{Key|F}}x to select them. The other users have a [[GNOME Display Manager|GDM]] login screen and can use xorg-server normally, but have no vt's.

Even though a single user can utilize multiple monitors connected to the different ports of a single graphics card (cf. RandR), the method which is based on multiple instances of the xorg-server seems to require multiple [[Conventional PCI|PCI]] graphics cards.

It is possible to configure multi-seat employing only one graphics card, but due to limitations of the X protocol this necessitates the usage of [[X Display Manager Control Protocol]] XDMCP.<ref>{{Cite web|url=https://help.ubuntu.com/community/MultiseatOneCard|title=MultiseatOneCard – Community Help Wiki|website=help.ubuntu.com}}</ref>

There is also [[Xdmx]] (Distributed Multihead X).

==Adoption==
; Unix and Linux
: The X.Org Server runs on many free-software [[Unix-like]] operating systems, including being adopted for use by most [[Linux distribution]]s and [[Berkeley Software Distribution|BSD]] variants. It is also the X server for the [[Solaris (operating system)|Solaris]] operating system. X.Org is also available in the repositories of [[MINIX|Minix 3]].
; Windows
: [[Cygwin/X]], [[Cygwin]]'s implementation of the X server for [[Microsoft Windows]], uses the X.Org Server, as do VcXsrv<ref>{{cite web|url=https://github.com/marchaesen/vcxsrv |title=VcXsrv Windows X Server |publisher=Github.com |access-date=2024-02-07}}</ref> ([[Visual C++]] X-server<ref>{{cite web
 | url        = https://vcxsrv.sourceforge.net/
 | title      = VcXsrv Windows X Server
 | website    = SourceForge.net
 | access-date = 2013-06-23
 | quote      = Windows X-server based on the xorg git sources (like xming or cygwin's xwin), but compiled with Visual C++ 2010.}}</ref>) and [[Xming]]. SSH clients such as [[PuTTY]] allow launching of X applications through X11 forwarding on the condition that it is enabled on both the server and client.
; OS X / macOS
: [[OS X]] versions prior to [[Mac OS X Leopard]] (10.5) shipped with an XFree86-based server, but 10.5's X server adopted the X.Org codebase.<ref>[http://lists.apple.com/archives/x11-users/2007/Jun/msg00026.html Re: Xorg in Leopard?] {{Webarchive|url=https://web.archive.org/web/20120213233353/http://lists.apple.com/archives/x11-users/2007/Jun/msg00026.html |date=13 February 2012 }}, From: Ben Byer, Date: 29 June 2007, Apple Mailing Lists</ref> Starting with [[OS X Mountain Lion]], (10.8) X11 is not bundled in OS X; instead, it has to be installed from, for example, the open source [[XQuartz]] project.<ref>{{cite web | url=http://www.macrumors.com/2012/02/17/apple-removes-x11-in-os-x-mountain-lion-shifts-support-to-open-source-xquartz/ | title=Apple Removes X11 in OS X Mountain Lion, Shifts Support to Open Source XQuartz | publisher=MacRumors | date=17 February 2012 | access-date=23 February 2012 |last=Slivka |first=Eric}}</ref> As of version 2.7.4, X11.app/XQuartz does not expose support for high-resolution [[Retina display]]s to X11 apps, which run in pixel-doubled mode on high-resolution displays.
; OpenVMS
: Current versions of the DECwindows X11 server for [[OpenVMS]] are based on X.org Server.<ref name="vms-8.4-spd">{{cite web
 | url = https://vmssoftware.com/docs/VSI_OVMS_SPDQS_OS_V842L1I_UPD1.pdf
 | title = Software Product Description and QuickSpecs – VSI OpenVMS Version 8.4-2L1 for Integrity servers
 | publisher = VMS Software Inc.
 | date = July 2019
 | access-date = 2021-01-02
}}</ref>

==History==
{{Main|X Window System#Release history|l1=Release history of the X Window System}}
[[File:Schema of the layers of the graphical user interface.svg|upright=1.5|thumb|A display server, such as X.Org Server, implements the [[windowing system]] and serves its clients.]]
The modern [[X.Org Foundation]] came into being in 2004 when the body that oversaw X standards and published the official reference implementation joined forces with former [[XFree86]] developers.<ref>{{cite web|last=Coopersmith|first=Alan|title=The difference between Xorg and XFree86|url=https://blogs.oracle.com/solaris/the-difference-between-xorg-and-xfree86-v2|date=28 May 2004|access-date=17 September 2018}}</ref> X11R6.7.0, the first version of the X.Org Server, was [[Fork (software development)|fork]]ed from XFree86 4.4 RC2.<ref name="announceX11R6.7" /> The immediate reason for the fork was a disagreement with the new license for the final release version of XFree86 4.4, but several disagreements among the contributors surfaced prior to the split. Many of the previous XFree86 developers have joined the X.Org Server project.

In 2005, a great effort was put in the modularization of the X.Org server source code,<ref>{{cite web|title=X.Org Foundation Modularization Working Group|url=http://www.x.org/wiki/ModularizationWorkingGroup/|publisher=X.Org Foundation|access-date=6 February 2014}}</ref> resulting in a dual release by the end of the year. The X11R7.0.0 release added a new modular build system based on the [[GNU Autotools]], while X11R6.9.0 kept the old [[imake]] build system, both releases sharing the same codebase. Since then the X11R6.9 branch is maintained frozen and all the ongoing development is done to the modular branch. The new build system also brought the use of dlloader standard [[dynamic linker]] to load plugins and drivers, deprecating the old own method. As a consequence of the modularization, the X11 binaries were moving out of their own <code>/usr/X11R6</code> subdirectory tree and into the global <code>/usr</code> tree on many [[Unix]] systems.

In June 2006, another effort was done to move the X.Org server source codebase from [[Concurrent Versions System|CVS]] to [[Git (software)|git]].<ref>{{cite web|last=Høgsberg|first=Kristian|title=Doing git migration now|date=July 2006 |url=http://lists.x.org/archives/xorg/2006-June/016439.html|access-date=6 February 2014}}</ref> Both efforts had the long-term goal of bringing new developers to the project. In the words of Alan Coopersmith:<ref>{{cite web|last=Coopersmith|first=Alan|title=Some times it's a book sprint, other times it's a marathon|url=https://blogs.oracle.com/solaris/some-times-its-a-book-sprint%2c-other-times-its-a-marathon-v2|access-date=12 January 2019}}</ref>

{{blockquote|Some of our efforts here have been technological – one of the driving efforts of the conversions from Imake to automake and from CVS to git was to make use of tools developers would already be familiar and productive with from other projects. The Modularization project, which broke up X.Org from one giant tree into over 200 small ones, had the goal of making it possible to fix a bug in a single library or driver without having to download and build many megabytes of software & fonts that were not being changed.}}

In the 7.1 release, the KDrive framework (a small implementation of X written by [[Keith Packard]], which was not based on [[XFree86]] that X.Org developers used as a testing ground for new ideas, such as [[EXA]]) was integrated into the main codebase of X.Org server.

In 2008, the new DRI2, based on the [[kernel mode-setting]] (KMS) driver, replaced DRI. This change also set a major milestone in the X.Org server architecture, as the drivers were moved out from the server and [[user space]] (UMS) to the [[kernel space]].

In 2013, the initial versions of DRI3 and Present extensions were written and coded by Keith Packard to provide a faster and [[Screen tearing|tearing]]-free 2D rendering. By the end of the year the implementation of [[GLX]] was rewritten by Adam Jackson at [[Red Hat]].<ref>{{cite web |url=https://www.phoronix.com/scan.php?page=news_item&px=MTQ2OTY |title=The X.Org Server's GLX Is Being Rewritten |date=26 October 2013}}</ref>

In June 2025, an unofficial fork of X.Org Server called Xlibre was released.<ref>{{Cite news |url=https://linuxiac.com/xlibre-xserver-project-plans-revival-of-x11/ |title=XLibre Xserver: Banned by Red Hat Developer Plans Revival of X11 |last=Borisov |first=Bobby |date=7 June 2025 |access-date=22 October 2025 |work=Linuxiac}}</ref><ref name="xlibrph">{{cite web  |title=XLibre 25.0 Released As Inaugural Version Of X.Org Server Fork |url=https://www.phoronix.com/news/XLibre-25.0-Released |website=[[Phoronix]] |access-date=29 October 2025}}</ref>

===Releases===
{{See also|X Window System#Release history|XFree86#Release history}}

{|class="wikitable sortable"
!Version
!Date
!X11 Release
!Main features
|-
|{{Version|o|1.0|sortKey=1.0}}
|{{dts|format=dmy|2005|12|21}}<ref name="announceX11R7.0">{{cite web|title=X11R6.9 and X11R7.0 Officially Released|url=http://www.x.org/wiki/Other/Press/X11R6970Released/|website=X.org|access-date=7 February 2015}}</ref>
|X11R7.0 (1.0.1)
|Initial modularized X server, [[EXA]] architecture
|-
|{{Version|o|1.1|sortKey=1.1}}
|{{dts|format=dmy|2006|05|22}}<ref name="announce1.1">{{cite web|last1=Jackson|first1=Adam|title=[ANNOUNCE] xorg-server 1.1.0|url=http://lists.x.org/archives/xorg-announce/2006-May/000087.html|website=X.org|date=22 May 2006 |access-date=7 February 2015}}</ref>
|X11R7.1 (1.1.0)
|KDrive integration, [[AIGLX]] support<ref>{{cite web|title=Summary of new features in X11R7.1|url=http://www.x.org/archive/X11R7.1/doc/RELNOTES2.html#2|website=X.org|access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.2|sortKey=1.2}}
|{{dts|format=dmy|2007|01|22}}<ref name="announce1.2">{{cite web|last1=Jackson|first1=Adam|title=[ANNOUNCE] xserver 1.2.0|url=http://lists.x.org/archives/xorg-announce/2007-January/000242.html|website=X.org|date=23 January 2007 |access-date=7 February 2015}}</ref>
|X11R7.2 (1.2.0)
|Autoconfiguration, enhanced support for GL-based compositing managers<ref>{{cite web|title=X11R7.2 Release|url=http://www.x.org/wiki/Releases/7.2/|website=X.org|access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.3|sortKey=1.3}}
|{{dts|format=dmy|2007|04|19}}<ref name="announce1.3">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.3.0.0 again|url=http://lists.freedesktop.org/archives/xorg/2007-April/023770.html|website=X.org|date=20 April 2007 |access-date=7 February 2015}}</ref>
|
|RandR 1.2<ref>{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.2.99.901 (X server 1.3 RC1)|url=http://lists.freedesktop.org/archives/xorg/2007-March/022190.html|website=X.org|date=5 March 2007 |access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.4|sortKey=1.4}}
|{{dts|format=dmy|2007|09|06}}<ref name="announce1.4">{{cite web|last1=Anholt|first1=Eric|title=[ANNOUNCE] xorg-server 1.4|url=http://lists.freedesktop.org/archives/xorg-announce/2007-September/000378.html|website=X.org|date=6 September 2007 |access-date=7 February 2015}}</ref>
|X11R7.3 (1.4.0)
|Input hotplugging support<ref name="announce1.4"/><ref>{{cite web|title=X server version 1.4 release plans|url=http://www.x.org/wiki/Server14Branch/|website=X.org|access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.5|sortKey=1.5}}
|{{dts|format=dmy|2008|09|03}}<ref name="announce1.5">{{cite web|last1=Jackson|first1=Adam|title=[ANNOUNCE] xserver 1.5.0|url=http://lists.freedesktop.org/archives/xorg-announce/2008-September/000640.html|website=X.org|date=3 September 2008 |access-date=7 February 2015}}</ref>
|X11R7.4 (1.5.1)
|[[Multi-Pointer X|MPX]]<ref>{{cite web |url=http://lists.freedesktop.org/archives/xorg/2008-May/035384.html |title=MPX has been merged |date=2008-05-26}}</ref>
|-
|{{Version|o|1.6|sortKey=1.6}}
|{{dts|format=dmy|2009|02|25}}<ref name="announce1.6">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.6.0|url=http://lists.x.org/archives/xorg-announce/2009-February/000784.html|website=X.org|date=25 February 2009 |access-date=7 February 2015}}</ref>
|
|RandR 1.3, [[Direct Rendering Infrastructure|DRI2]], XInput 1.5<ref>{{cite web|title=Server 1.6 branch|url=http://www.x.org/wiki/Server16Branch/|website=X.org|access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.7|sortKey=1.7}}
|{{dts|format=dmy|2009|10|01}}<ref name="announce1.7">{{cite web|last1=Hutterer|first1=Peter|title=[ANNOUNCE] xorg-server 1.7.0|url=http://lists.freedesktop.org/archives/xorg-announce/2009-October/001087.html|website=X.org|date=2 October 2009 |access-date=7 February 2015}}</ref>
|X11R7.5 (1.7.1)
|XInput 2.0, multi-pointer X<ref>{{cite web|title=Server 1.7 branch|url=http://www.x.org/wiki/Server17Branch/|website=X.org|access-date=7 February 2015}}</ref><ref>{{cite web|last1=Larabel|first1=Michael|title=X Server 1.7 Released With XI2/MPX Glory|url=https://www.phoronix.com/scan.php?page=news_item&px=NzU3OQ|website=Phoronix|access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.8|sortKey=1.8}}
|{{dts|format=dmy|2010|04|02}}<ref name="announce1.8">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.8.0|url=http://lists.freedesktop.org/archives/xorg/2010-April/049595.html|website=X.org|date=2 April 2010 |access-date=7 February 2015}}</ref>
|
|{{Mono|xorg.conf.d}}, udev input handling<ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.8.0 Is Here|url=https://www.phoronix.com/scan.php?page=news_item&px=ODExOA|website=Phoronix|access-date=7 February 2015}}</ref>
|-
|{{Version|o|1.9|sortKey=1.9}}
|{{dts|format=dmy|2010|08|20}}<ref name="announce1.9">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.9.0|url=http://lists.freedesktop.org/archives/xorg-announce/2010-August/001390.html|website=X.org|date=21 August 2010 |access-date=7 February 2015}}</ref>
|X11R7.6 (1.9.3)
|
|-
|{{Version|o|1.10|sortKey=1.10}}
|{{dts|format=dmy|2011|02|25}}<ref name="announce1.10">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.10.0|url=http://lists.freedesktop.org/archives/xorg-announce/2011-February/001612.html|website=X.org|date=26 February 2011 |access-date=7 February 2015}}</ref>
|
|X Synchronization Fences<ref>{{cite web|last1=Larabel|first1=Michael|title=That Was Quick, X Server 1.10 Officially Released|url=https://www.phoronix.com/scan.php?page=news_item&px=OTEzOA|website=Phoronix|access-date=8 February 2015}}</ref>
|-
|{{Version|o|1.11|sortKey=1.11}}
|{{dts|format=dmy|2011|08|26}}<ref name="announce1.11">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.11.0|url=http://lists.x.org/archives/xorg-announce/2011-August/001729.html|website=X.org|date=27 August 2011 |access-date=7 February 2015}}</ref>
|
|
|-
|{{Version|o|1.12|sortKey=1.12}}
|{{dts|format=dmy|2012|03|04}}<ref name="announce1.12">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.12.0|url=http://lists.x.org/archives/xorg-announce/2012-March/001846.html|website=X.org|date=5 March 2012 |access-date=7 February 2015}}</ref>
|X11R7.7 (1.12.2)
|XInput 2.2 (including multi-touch support)<ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.12 Released With Multi-Touch|url=https://www.phoronix.com/scan.php?page=news_item&px=MTA2NjE|website=Phoronix|access-date=8 February 2015}}</ref>
|-
|{{Version|o|1.13|sortKey=1.13}}
|{{dts|format=dmy|2012|09|05}}<ref name="announce1.13">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.13.0|url=http://lists.x.org/archives/xorg-announce/2012-September/002068.html|website=X.org|date=5 September 2012 |access-date=7 February 2015}}</ref>
|
|New DDX driver API, [[Direct Rendering Infrastructure|DRI2]] offload, RandR 1.4, [[OpenGL]] 3.x+ contexts, removing [[XFree86 Acceleration Architecture|XAA]]<ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.13 Released With Massive Changes|url=https://www.phoronix.com/scan.php?page=news_item&px=MTE3Njg|website=Phoronix|access-date=8 February 2015}}</ref>
|-
|{{Version|o|1.14|sortKey=1.14}}
|{{dts|format=dmy|2013|03|05}}<ref name="announce1.14">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.14.0|url=http://lists.x.org/archives/xorg-announce/2013-March/002179.html|website=X.org|date=6 March 2013 |access-date=7 February 2015}}</ref>
|
|XInput 2.3<ref>{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.13.99.901 (1.14 RC1)|url=http://lists.freedesktop.org/archives/xorg/2012-December/055197.html|website=X.org|date=19 December 2012 |access-date=9 February 2015}}</ref>
|-
|{{Version|o|1.15|sortKey=1.15}}
|{{dts|format=dmy|2013|12|27}}<ref name="announce1.15">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.15.0|url=http://lists.x.org/archives/xorg-announce/2013-December/002384.html|website=X.org|date=27 December 2013 |access-date=7 February 2015}}</ref>
|
|DRI3 and Present extensions<ref>{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.14.99.901|url=http://lists.freedesktop.org/archives/xorg/2013-November/056148.html|website=X.org|date=November 2013 |access-date=9 February 2015}}</ref><ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.15 Release Has Several New Features|url=https://www.phoronix.com/scan.php?page=news_item&px=MTU1NDQ|website=Phoronix|access-date=9 February 2015}}</ref>
|-
|{{Version|o|1.16|sortKey=1.16}}
|{{dts|format=dmy|2014|07|17}}<ref name="announce1.16">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.16.0|url=http://lists.x.org/archives/xorg-announce/2014-July/002457.html|website=X.org|date=17 July 2014 |access-date=7 February 2015}}</ref>
|
|XWayland DDX, GLAMOR acceleration, non-PCI devices support, [[Logind|systemd-logind]] support (rootless X),<ref name="announce1.16"/><ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.16 Officially Released With Terrific Features|url=https://www.phoronix.com/scan.php?page=article&item=xorg_server_116&num=1|website=Phoronix|access-date=9 February 2015}}</ref> obtained support for the [[libinput]] library in form of a wrapper called <code>xf86-input-libinput</code><ref name="Hutterer 2014">{{cite web|last1=Hutterer|first1=Peter|title=libinput – a common input stack for Wayland compositors and X.Org drivers|url=http://who-t.blogspot.com/2014/09/libinput-common-input-stack-for-wayland.html|date=24 September 2014|access-date=17 April 2016}}</ref><ref name="libinputfosdem15">{{cite web|last1=de Goede|first1=Hans|title=Replacing xorg input – Drivers with libinput|url=https://archive.fosdem.org/2015/schedule/event/libinput/attachments/slides/591/export/events/attachments/libinput/slides/591/libinput_xorg.pdf|date=1 February 2015|access-date=18 April 2016}}</ref>
|-
|{{Version|o|1.17|sortKey=1.17}}
|{{dts|format=dmy|2015|02|04}}<ref name="announce1.17">{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.17.0|url=http://lists.x.org/archives/xorg-announce/2015-February/002529.html|website=X.org|date=4 February 2015 |access-date=7 February 2015}}</ref>
|
|Integration of the former <code>xf86-video-modesetting</code> generic DRM/KMS driver,<ref>{{cite web|last1=Packard|first1=Keith|title=[ANNOUNCE] xorg-server 1.16.99.901|url=http://lists.x.org/archives/xorg-announce/2014-October/002491.html|website=X.org|date=29 October 2014 |access-date=9 February 2015}}</ref><ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.17 Officially Released|url=https://www.phoronix.com/scan.php?page=news_item&px=X.Org-Server-1.17-Released|website=Phoronix|access-date=9 February 2015}}</ref> added support for [[Direct Rendering Infrastructure#DRI2|DRI2]] with GLAMOR
|-
|{{Version|o|1.18|sortKey=1.18}}
|{{dts|format=dmy|2015|11|09}}<ref name="announce1.18">{{cite mailing list|url=http://lists.x.org/archives/xorg-announce/2015-November/002655.html|title=[ANNOUNCE] xorg-server 1.18.0|first=Adam|last=Jackson|date=9 November 2015|mailing-list=xorg-announce}}</ref>
|
|RandR 1.5
|-
|{{Version|o|1.19|sortKey=1.19}}
|{{dts|format=dmy|2016|11|15}}<ref name="announce1.19">{{cite mailing list|url=https://lists.x.org/archives/xorg-announce/2016-November/002737.html|title=[ANNOUNCE] xorg-server 1.19.0|first=Keith|last=Packard|date=15 November 2016|mailing-list=xorg-announce}}</ref>
|
|Threaded Input, PRIME synchronization, XWayland pointer confinement and warping, Windows DRI extension support<ref>{{cite web|last1=Larabel|first1=Michael|title=X.Org Server 1.19 Officially Released With A Year's Worth Of Improvements|url=http://phoronix.com/scan.php?page=news_item&px=X.Org-Server-1.19-Released|website=Phoronix|access-date=15 November 2016}}</ref>
|-
|{{Version|o|1.20|sortKey=1.20}}
|{{dts|format=dmy|2018|05|10}}<ref name="announce1.20">{{cite mailing list|url=https://lists.x.org/archives/xorg-announce/2018-May/002893.html|title=[ANNOUNCE] xorg-server 1.20|first=Adam|last=Jackson|date=10 May 2018|mailing-list=xorg-announce}}</ref>
|
|[[Meson (software)|Meson]] build system improvements, GLXVND allows for distinct OpenGL drivers for different X screens, RandR leasing improves [[Steam VR]] support
|-
|{{Version|c|21.1|sortKey=21.1}}
|{{dts|format=dmy|2021|10|27}}<ref name="announce21.1">{{cite mailing list|url=https://lists.x.org/archives/xorg-announce/2021-October/003115.html|title= [ANNOUNCE] xorg-server 21.1.0|first=Povilas|last=Kanapickas |date=27 October 2021|mailing-list=xorg-announce}}</ref>
|
|Meson build system now on par with Autotools, [[Variable refresh rate]] support, touchpad gestures via XInput 2.4
|-
|colspan=4 |{{Version|l|show=111101}}
|}

==See also==
{{Portal|Free and open-source software}}
{{Div col|colwidth=25em}}
* [[Reference implementation]]{{snd}} part of a standard release package
* [[X window manager]]{{snd}} a package that is deliberately kept separate from the X server package
* [[X video extension]]
* [[evdev]]
* [[xorg.conf]]
* [[XQuartz]] – An X server for macOS
*[[Xming]] – An X server for Windows
* [[Xenocara]]
{{div col end}}

==References==
{{Reflist|30em}}

==External links==
{{Commons category}}
* {{Official website|https://www.x.org/}}
* [https://github.com/marchaesen/vcxsrv VcXsrv] – a fully updated X server for Windows
* [https://sourceforge.net/projects/vcxsrv/ VcXsrv] – SourceForge old repository for Windows

{{XWinSys}}
{{Freedesktop.org}}

[[Category:X servers]]
[[Category:Freedesktop.org]]
[[Category:Software forks]]
[[Category:Software that uses Meson]]