Table of Contents
via - VIA unichrome graphics driver
Section "Device"
Identifier "devname"
Driver "via"
...
EndSection
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, PM8X0 and CN400 support
is still under development.
Direct rendering 3D is available using experimental
drivers in Mesa, www.mesa3d.org. Also there is an XvMC client library for
hardware MPEG1 / MPEG2 decoding acceleration available on the CLE266 and
K8M/N800 chipsets 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.
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 some EPIA boards the composite video port is shared
with audio out and jumper selected.
- 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 "EnableAGPDMA" "boolean"
- Enable the
AGP DMA functionality in DRM. This requires that DRI is enabled and will
force 2D, and 3D acceleration to use AGP DMA. The XvMC DRI client will also
make use of this on the CLE266 to consume much less CPU.
- Option "NoAGPFor2D"
"boolean"
- With this option on, 2D acceleration will not use AGP DMA even
if it is enabled.
Unichromes tend to be paired with
several different TV Encoders.
- VIA Technologies VT1621
- Untested as no combination
with Unichrome is known or available. Supports the following normal modes:
"640x480" and "800x600". Use "640x480Over" and "800x600Over" for vertical
overscan. These modes are made available by the driver and modelines provided
in xorg.conf will be ignored.
- VIA Technologies VT1622, VT1622A, VT1623
- Supports
the following modes: "640x480", "800x600", "1024x768", "848x480", "720x480"
(NTSC only) and "720x576" (PAL only). Use "640x480Over", "800x600Over",
"1024x768Over", "848x480Over", "720x480Over" (NTSC) and "720x576Over" (PAL)
for vertical overscan. The modes "720x480Noscale" (NTSC) and "720x576Noscale"
(PAL) (VT1622 only) provide cleaner TV output (unscaled with only minimal
overscan). These modes are made available by the driver and modelines provided
in xorg.conf will be ignored.
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.
Xorg(1x)
, xorg.conf(5x)
, xorgconfig(1x)
,
Xserver(1x)
, X(7x)
Authors include: ...
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