<!DOCTYPE linuxdoc PUBLIC "-//XFree86//DTD linuxdoc//EN">

<article>
<title>Information for Cyrix Chipset Users
<author>The XFree86 Project Inc.
<date>22 June 1999
<toc>

<sect>Supported hardware <p>

This driver (as used in the SVGA (VGA256), VGA16 and VGA_Mono servers) 
supports a single chipset `mediagx' that should work on the following Cyrix
CPUs with integrated graphics:

<itemize>
<item>MediaGX
<item>MediaGXi
<item>MediaGXm
</itemize>

<sect>Features <p>
<itemize>
<item>accelerated
<item>hardware cursor
<item>support color depths 1, 4, 8 and 16
</itemize>

<sect>XF86Config Option <p>
<descrip>
<tag>Option "sw_cursor"</tag>
disable the hardware cursor.
<tag>Option "no_accel"</tag>
completely disables acceleration. Usually not recommended.
</descrip>

<sect>Bugs and Limitations<p>
<itemize>
<item>On some older chipsets, the driver may trigger an illegal instruction
just after probing for the ``scratchpad size''.  If this is the case,
email to hecker@cat.dfrc.nasa.gov with the output of 
<verb>
XF86_SVGA -probeonly -verbose
</verb>
and this will be fixed.
<item>There are limitations to the modeline values that can be specified.
Particularly, the difference between the first two horizontal
timings (e.g. 640 656, 1024 1048) must be at least 16 and at most 24.
The modeline values are not used in the 3.3.4 server since there is a
static array used to load the registers.  The modeline only identifies
that a particular resolution is desired.  The standard VESA modes up
to 1280x768 are supported.  For more specific information, consult
the source code.
<item>The 4 colour server is slow due to the VGA banking mode used.
Moreover,
it does not work the way it is run by XF86Setup, which is probably
due to the timing limitations.
<item>The 3.3.4 server MAY totally hang the machine at times.  It is
reported to be stable on a BSD platform using twm.  It has crashed
when using resolutions greater than 800x600 on a Linux (Debian 
based) system using wm as the window manager.  The safest course is
to use the 3.3.3.1 server instead.  Efforts are under way to resolve
this issue and provide a more robust server under the 4.x release.

</itemize>

<sect>Authors<p>
<itemize>
<item>Annius Groenink <it>&lt;Annius.Groenink@cwi.nl&gt;</it>
<item>Dirk Hohndel <it>&lt;hohndel@XFree86.org&gt;</it>
<item>Brian Falardeau 
<item>Special thanks to Cyrix and Wyse for helping us with the development of
this server.  Brian, a Cyrix employee, made the 3.3.4 update possible since
the new 4.0 server has been our top priority.
</itemize>

<verb>
$XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/cyrix.sgml,v 1.1.2.4 1999/06/24 06:16:44 hohndel Exp $
</verb>

</article>

