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, 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 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.
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.
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", "DFP",
"TV" should be possible. "CRT" represents anything that is connected to
the VGA port, "LCD" and "DFP" are for laptop panels (not TFT screens attached
to the VGA port), "TV" is self explanatory. 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. Particularly 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 downlads (if DRI is enabled) and the Render / Composite
extension.
- Option "EXANoComposite" "boolean"
- If Exa is enabled using the
above option, Don't accelerate composite. Since EXA, and in particular, it's
composite acceleration is still experimental, This is a way to disable
exa composite acceleration.
- Option "ExaScratchSize" "integer"
- Set the size
of the exa scratch area to "integer" kB. This area is used by EXA as a last
place to look for available space for pixmaps. Too little space and compositing
will slow down. This should be set to the size of the largest pixmap used.
If you have screen width of over 1024 and use 24Bpp, set this to 8192. Otherwise
you can leave this with the default 4096. The space will be allocated from
AGP memory if available. Otherwise from VRAM.
- Option "MigrationHeuristic"
"string"
- Set the migration heuristic for EXA pixmap migration. This is an
EXA core option, and on Xorg xserver versions after 1.1.0, this defaults
to "smart", otherwise to "greedy". The openChrome driver performs best with
the "greedy" option, so you should really add this option. The third option
is "always", which might become more useful in the future.
- Option "MaxDRIMem"
"integer"
- Set the maximum amount of VRAM memory allocated for DRI clients.
Normally they get half the available VRAM size, but in some cases it might
make sense to limit this amount of memory. For example if you are using
a composite manager and you want to get as much memory as possible to the
EXA pixmap storage area. DRI VRAM will be limited to "integer" kB.
- Option
"AGPMem" "integer"
- Set the amount of AGP memory allocated at X server startup.
The AGP memory allocated will be "integer" kB. The AGP memory is used for
the AGP command buffer (If option EnableAGPDMA is set to "true"), DRI textures
and for the EXA scratch area. The driver will allocate at least one system
page of AGP memory and if the AGP command buffer is used, at least 2MB
+ one system page. If there is no room for the EXA scratch area in AGP space,
it will be allocated from VRAM. If there is no room for DRI textures they
will be allocated from the DRI part of VRAM. See "Option "MaxDRIMem"". The
default amount of AGP is 32768kB. Note that the AGP aperture set in BIOS
must be able to accomodate the amount of AGP memory specified here. Otherwise
"no" AGP memory will be available. It is safe to set a very large AGP aperture
in BIOS.
- Option "VBEModes" "boolean"
- Use the VBE bios calls to set the display
mode. This mimics the behaviour of the vesa video driver but still provides
acceleration and other features. This option may be used if your hardware
works with the vesa driver, but not with the openChrome driver. May not
work on 64-bit systems. Using VBEModes may speed up driver acceleration significantly
due to a more agressive hardware setting. Particularly on systems with low
memory bandwidth. Your refresh rate may be limited to 60Hz on some systems.
- Option "VBESaveRestore" "boolean"
- Use the VBE bios calls to save and restore
the display state when the X server is launched. This can be extremely slow
on some hardware. And the system may appear to have locked for 10 seconds
or so. The default is to use the driver builtin function. This option only
works if VBEModes 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.
Xorg(1x)
, xorg.conf(5x)
,
xorgconfig(1x)
, Xserver(1x)
, X(7x)
Authors include: ...
Table of Contents