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<title>Information for SiS Users
<author>Thomas Winischhofer (<email>thomas@winischhofer.net</email>)
<date>5 October 2003

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<sect> Introduction <p>

This driver is written by Thomas Winischhofer and is a (nearly) complete re-write
of a driver written for the SiS6326 and SiS530 by Alan Hourihane and others.

It currently supports the following chipsets:
<itemize>
   <item>old series: 5597/5598, 6236/AGP/DVD, 530/620
   <item>300 series: 300/305, 540, 630/730
   <item>315 series: 315, 550, 650, 651, M650, 740
   <item>330 series: 330 ("Xabre"), 661FX, M661FX, 741, 760
</itemize>

The driver supports:
<itemize>
  <item>8/16/24 bits color depth; old series also 15;
  <item>XAA 
  <item>XVideo (Xv)
  <item>Render (XRAND)
  <item>Hardware cursor; 315/330 series: Color HW cursor;
  <item>6326: TV output
  <item>300/315/330 series: TV output via Chrontel TV encoders or SiS video bridges
  <item>300/315/330 series: LCD output via LVDS transmitters or SiS video bridges
  <item>300/315/330 series: Dual head mode; Xinerama; Merged framebuffer mode;
</itemize>

This document gives an overview over the driver's features and configuration options.
Please see http://www.winischhofer.net/linuxsisvga.shtml for detailed documentation
and updates. Support for the 661, 741 and 760 is entirely untested as of this writing,
and possibly incomplete for LCD output.

<sect> xorg.conf Options <p>

The following options are of particular interest for the SiS
driver. Each of them must be specified in the Device section of the
xorg.conf file for this card.

<sect1>For all chipsets<p>

<descrip>
<tag>Option "SWCursor", "HWCursor"</tag>
	These options select whether the software (SW) or hardware (HW) cursor should
	be used. The default is using the hardware cursor.
<tag>Option "NoAccel"</tag>
        Disables 2D acceleration. Default: 2D acceleration is enabled.
<tag>Option "Turboqueue"</tag>
	SiS chipsets have the option to extend the engine command queue on
	VRAM. This concept is called "TurboQueue" and gives some performance improvement.
	Due to hardware bugs, the TurboQueue is disabled on the 530/620, otherwise
	enabled by default.
<tag>Option "Rotate"</tag>
        This option enables clockwise ("CW") or counter-clockwise ("CCW") rotation of
	the display. Enabling either CW or CCW rotation disables the RandR extension.
	Default: no rotation.
<tag>Option "ShadowFB"</tag>
        This option enables the shadow framebuffer layer. By default, it is disabled.
<tag>Option "NoXVideo"</tag>
        Disables the XVideo support. Default: XVideo support is enabled.
<tag>Option "CRT1Gamma"</tag>
        Enables or disables gamma correction. Default: gamma correction is enabled.
</descrip>

<sect1>old series specific options <p>

<descrip>
<tag>Option "FastVram"</tag>
        Enables 1 cycle memory access for read and write operations. The default
	depends on the chipset used.
<tag>Option "NoHostBus"</tag>
        For 5597/5598 only. This option, if set, disables the CPU to VGA host bus.
	Disabling the host bus will result in a severe performance regression.
<tag>VideoRAM size</tag> The SiS 6326 can only directly address 4096K
        bytes of video RAM. However, there are some cards out there featuring
	8192K (8MB) of video RAM. This RAM is not addressable by the engines.
	Therefore, by default, the driver will only use 4096K. This behavior
	can be overridden by specifying the amount of video RAM using the
	VideoRAM keyword. If more than 4096K is specified, the driver will
	disable 2D acceleration, Xv and the HW cursor. On all other chipsets,
	this keyword is ignored.
<tag>Option "NoYV12"</tag>
        Due to hardware bugs, XVideo may display a corrupt image when using
	YV12 encoded material. This option, if set, disables support for YV12
	and hence forces the Xv-aware application to use either YUV2 or XShm
	for video output.
<tag>Option "TVStandard"</tag>
	(6326 only) Selects the TV output standard. May be PAL or NTSC. By default,
	this is selected by a jumper on the card.
</descrip>

<sect1>300/315/330 series specific options<p>

<descrip>
<tag>Option "ForceCRT1"</tag>
        Enables or disables CRT1 (= the external VGA monitor). By default,
	the driver will use CRT1 if a monitor is detected during server
	start. Some older monitors can't be detected, so they may require
	setting this option to true. To disable CRT1 output, set this option
	to false.
<tag>Option "ForceCRT1Type"</tag>
 	SiS 650, M650 and 651 with either 301LV or 302LV video bridge only.
	May be VGA or LCD. Specifying LCD will force the driver to use the
	VGA controller's CRT1 channel for driving the LCD, while CRT2 is
	free for TV usage. Default is VGA.
<tag>Option "ForceCRT2Type"</tag>
    Selects the CRT2 output device type. Valid parameters are LCD, TV,
	SVIDEO, COMPOSITE, SCART, VGA, NONE. NONE disables CRT2. SVIDEO and
	COMPOSITE are only for systems with a SiS video bridge and select the
	desired plug type. For Chrontel systems, TV should be used instead.
	VGA means secondary VGA and is only available on some SiS video bridges
	(301, 301B, 301C).
<tag>Option "CRT2Gamma"</tag>
    Enables or disables gamma correction for CRT2. This is only supported
	for SiS video bridges. Default: gamma correction for CRT2 is enabled.
<tag>Option "DRI"</tag>
	Although this option is accepted for all chipsets, it currently only
	makes sense on the 300 series; DRI is only supported on these chipsets.
	This option enables/disables DRI.
<tag>Option "TVStandard"</tag>
	Selects the TV output standard. May be PAL or NTSC, on some machines
	(depending on the hardware) also PALM and PALN. Default: BIOS setting.
<tag>Option "TVXPosOffset", "TVYPosOffset"</tag>
	These options allow relocating the image on your TV. Both options take
	an integer within the range of -16 to 16. Default: 0. Not supported for
	Chrontel 7019.
<tag>Option "CHTVOverscan"</tag>
	For Chrontel TV encoders only. Selects whether TV output should be
	overscan or underscan.
<tag>Option "CHTVSuperOverscan"</tag>
	For Chrontel 7005 TV encoders in PAL mode only. Selects whether TV output
	should be super-overscan (slightly larger than the viewable area) or
	not.
<tag> Option "SISTVXScale", "SISTVYScale"</tag>
	For SiS video bridges only. These options allow zooming the image on
	your TV. SISTVXScale takes an integer within the range of -16 to 16.
	SISTVYScale accepts -4 to 3. Default: 0. Not all modes can be scaled.
</descrip>

<sect1> 300 series specific options<p>

<descrip>
<tag>Option "MaxXFBMem"</tag>
	DRI requires the linux kernel's SiS framebuffer driver "sisfb" and some
	other modules which come with either the linux kernel or X11R&relvers;. (On *BSD,
	the DRI driver does not require any framebuffer driver.)
  	Sisfb takes care of memory management for texture data. In order to prevent
	the X driver and sisfb from overwriting each others video memory, sisfb
	reserves an amount of video memory for the X driver. This amount can either
	be selected using sisfb's mem parameter, or auto-selected depending on the
	amount of total video RAM available. However, the X driver needs to know about
	the amount of RAM sisfb reserved. For this purpose, the Option "MaxXFBMem" exists.

	XFree 4.3.0 disabled SiS DRI support due to a lack of maintenance of the SiS DRI
	driver. X11R&relvers; and X11R&relvers; and XFree86 4.4 contains a newly written 
        SiS DRI driver by Eric Anholt.

	If you intend to use DRI, I recommend setting the total video memory in the BIOS
	to 64MB in order to at least overcome the lack of memory swap functions.

	Sisfb can be used for memory management only, or as a complete framebuffer driver.
	If you start sisfb with a valid mode (ie you gain a graphical console), the X driver
	can communicate with sisfb and doesn't require setting the MaxXFBMem option at all.
	The X driver will receive enough information from sisfb in this case.

	However, if you use sisfb for memory management only, ie you started sisfb with
	mode=none and still have a text mode console, there is no communication between sisfb
	and the X driver. In this case, you need to set MaxXFBMem to the same value as you
	gave sisfb with its mem parameter. If you didn't specify any mem parameter, sisfb
	will reserve 12288KB if more than 16MB of total video RAM is available, 8192KB if
	between 12 and 16MB of video RAM is available, 4096KB in all other cases.

	Then you need to specify any of these amounts as the parameter for the MaxXFBMem
	option. The value is to be given without 'KB'.
</descrip>

<sect1> 315/330 series specific options<p>

<descrip>
<tag>Option "RenderAcceleration"</tag>
	Enables or disables RENDER acceleration. By default, RENDER acceleration
	is enabled.
<tag>Option "XvOnCRT2"</tag>
	315, 650, 740, 330 only. This option selects whether the XVideo (Xv)
	overlay should be displayed on CRT1 or CRT2. Setting this options
	means CRT2. The other CRT will only display the (blue) color key.
</descrip>

Document based on 4.1 version written by Joanjo Santamarta and 3.3 version
written by Xavier Ducoin.

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