Editing X.Org Server (section)

====={{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]].