Table of Contents

Name

via - VIA unichrome graphics driver

Synopsis


Section "Device"
  Identifier "devname"
  Driver "via"
  ...
EndSection

Description

via is an Xorg driver for VIA chipsets with onboard unichrome graphics.

The via driver supports the VIA CLE266, KM400/KN400 chipsets, including 2D acceleration and the Xv video overlay extensions. Flat panel, TV and VGA outputs are supported.

K8M800/K8N800 support is still under development.

Direct rendering 3D is available as root only, but has some rendering glitches at this time. Also there is an XvMC client library for hardware MPEG1 / MPEG2 decoding acceleration available on the CLE266 chipset that uses the Direct Rendering Infrastructure, DRI. The XvMC client library implements a nonstandard "VLD" extension to the XvMC standard. The current Direct Rendering Manager Linux kernel module is available at dri.sourceforge.net.

Only a limited number of resolutions are supported at 60, 75, 85, 100 and 120Hz (save memory bandwidth limitations): 640x480, 800x600, 1024x768, 1152x864, 1280x1024 and 1600x1200. Another range of resolutions is only possible at 60Hz: 720x480, 720x576, 848x480, 856x480, 1024x512, 1024x576, 1280x768, 1280x960, 1400x1050 and 1440x1050. This behaviour will change in the not too distant future.

Configuration Details

Please refer to xorg.conf(5x) for general configuration details. This section only covers configuration details specific to this driver.

The following driver options are supported

Option "NoAccel" "boolean"
Disable or enable acceleration. Default: acceleration is enabled.
Option "HWCursor" "boolean"
Disable or enable use of hardware cursors. The default is enabled.
Option "SWCursor" "boolean"
Disable or enable the use of a software cursor. The default is disabled.
Option "ShadowFB" "boolean"
Use a shadow frame buffer. This is required when rotating the display, but otherwise defaults to disabled.
Option "VideoRAM" "boolean"
Override the VideoRAM auto detection. This should never be needed.
Option "Rotate" "string"
Rotate the display either clockwise ("CW") or counter clockwise ("CCW"). Rotation is only supported unaccelerated.
Option "ActiveDevice" "string"
Specify the active device combination. Any string containing "CRT", "LCD", "TV" should be possible. The default is to use what is detected. The driver is currently unable to use LCD and TV simultaneously, and will favour the LCD.
Option "LCDDualEdge" "boolean"
Use dual edge mode to set the LCD.
Option "Center" "boolean"
Disable or enable image centering on DVI displays.
Option "PanelSize" "string"
Specify the size (width x height) of the LCD panel attached to the system. Sizes 640x480, 800x600, 1024x768, 1280x1024, and 1400x1050 are supported.
Option "TVDotCrawl" "boolean"
Disable or enable dotcrawl.
Option "TVDeflicker" "integer"
Specify deflicker setting for TV output. Valid values are 0,1,2 0) No deflicker, 1) 1:1:1 deflicker, 2) 1:2:1 deflicker.
Option "TVType" "string"
Specify TV output format. The driver currently supports "NTSC" and "PAL" timings only.
Option "TVOutput" "string"
Specify which TV output to use. The driver supports "S-Video", "Composite", "SC", "RGB" and "YCbCr" outputs. Note that on many boards the composite video port is shared with audio out and jumper selected.
Option "TVVScan" "string"
Specify whether to underscan the TV image (bordering it with black), or overscan it (losing the edges of the picture). Possible values are "under" (not currently functional) and "over".
Option "DisableVQ" "boolean"
Disable or enable the use of VQ. VQ is enabled by default.
Option "DRIXINERAMA" "boolean"
Set DRI Xinerama mode. Currently unsupported.
Option "DisableIRQ" "boolean"
Disables Vblank IRQ. A workaround for some mainboards that have problems with IRQs from the unichrome chip. With IRQ disabled, DRI clients have no way to sync drawing to Vblank.
Option "AllowInsecureDRI" "boolean"
Opens up the register space of the unichrome chip to authenticated DRI clients. Not just root. This allows 3D OpenGL DRI clients to be run as normal users if the DRI permissions are set to allow that. A carefully crafted DRI client could exploit this to gain access to all memory pages of the system, and therefore this option is a considerable security risc, and should not be used. If you are the only user on a system that is not connected to the internet, or are aware of the risc you are taking, you might consider using it. Another option is to run OpenGL programs as root.
Option "EnableAGPDMA" "boolean"
Enable the AGP DMA functionality in DRM. This requires that DRI is enabled and will force 2D acceleration to use AGP DMA. The XvMC DRI client will also make use of this to consume much less CPU. This does not work with the current 3D driver, though. Therefore it is off by default. It is also mutually exclusive with option "AllowInsecureDRI", so if that option is enabled, AGP DMA will be turned off.
Option "NoAGPFor2D" "boolean"
With this option on, 2D acceleration will not use AGP DMA even if it is enabled.

Bugs

Switching virtual terminals when an OpenGL DRI client is running may cause subsequent rendering errors or server crash. XvMC DRI does not suffer from this.

See Also

Xorg(1x) , xorg.conf(5x) , xorgconfig(1x) , Xserver(1x) , X(7x)

Authors

Authors include: ...


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