VIA(4) VIA(4)
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, K8M/N800, PM/N800
and CN400 chipsets, including 2D acceleration and the Xv video overlay
extensions. Flat panel, TV and VGA outputs are supported, depending on
the hardware configuration.
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, CN400,
PM/N800 and K8M/N800 chipsets that uses the Direct Rendering Infras-
tructure, 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.
The driver supports free modes for Unichome Pro chipsets. (K8M/N800,
PM/N800 and CN400). Currently for Unichrome chipsets, it only supports
a limited number of dotclocks, so if you are using X modelines, you
must make sure that the dotclock is one of those supported. Supported
dotclocks on Unichromes are currently (MHz): 25.2, 25.312, 26.591,
31.5, 31.704, 32.663, 33.750, 35.5, 36.0, 39.822, 40.0, 41.164, 46.981,
49.5, 50.0, 56.3, 57.284, 64.995, 65.0, 65.028, 74.480, 75.0, 78.8,
81.613, 94.5, 108.0, 108.28, 122.0, 122.726, 135.0, 148.5, 155.8,
157.5, 161.793, 162.0, 175.5, 189.0, 202.5, 204.8, 218.3, 229.5. On top
of this, bandwidth restrictions apply both for Unichromes and Unichrome
Pros.
CONFIGURATION DETAILS
Please refer to xorg.conf(5) 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.
Option "NoXVDMA" "boolean"
If DRI is enabled, Xv normally uses PCI DMA to transfer video
images from system to frame-buffer memory. This is somewhat
slower than direct copies due to the limitations of the PCI bus,
but on the other hand it decreases CPU usage significantly. Par-
ticularly on computers with fast processors. Some video players
are buggy and will display rendering artifacts when PCI DMA is
used. If you experience this, or don't want your PCI bus to be
stressed with Xv images, set this option to "true". This option
has no effect if DRI is not enabled.
Option "AccelMethod" "string"
The driver supports "XAA" and "EXA" acceleration methods. The
default method is XAA, since EXA is still experimental. Contrary
to XAA. EXA implements acceleration for screen uploads and down-
lads (if DRI is enabled) and the Render / Composite extension.
Option "EXANoComposite" "boolean"
If Exa is enabled using the above option, Don't accelerate com-
posite. Since EXA, and in particular, it's composite accelera-
tion is still experimental, This is a way to disable exa compos-
ite acceleration.
Supported TV Encoders
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 over-
scan. 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.
SEE ALSO
Xorg(1), xorg.conf(5), xorgconfig(1), Xserver(1), X(7)
AUTHORS
Authors include: ...
X Version 11 xf86-video-via 0.2.1 VIA(4)
