Provided by: xserver-xorg-video-openchrome_0.6.0-3build1_amd64 
NAME
openchrome - video driver for VIA Unichromes
SYNOPSIS
Section "Device"
Identifier "devname"
Driver "openchrome"
...
EndSection
DESCRIPTION
openchrome is an Xorg driver for VIA chipsets that have an integrated Unichrome graphics engine.
The openchrome driver supports the following chipsets: CLE266, KM400/KN400/KM400A/P4M800,
CN400/PM800/PN800/PM880, K8M800, CN700/VM800/P4M800Pro, CX700, P4M890, K8M890, P4M900/VN896/CN896, VX800,
VX855 and VX900. The driver includes 2D acceleration and Xv video overlay extensions. Flat panel, TV,
and VGA outputs are supported, depending on the hardware configuration.
3D direct rendering is available using experimental drivers from Mesa (www.mesa3d.org). There is also an
XvMC client library for hardware acceleration of MPEG1/MPEG2 decoding (not available on the KM/N400) that
uses the Direct Rendering Infrastructure (DRI). The XvMC client library implements a non-standard "VLD"
extension to the XvMC standard. The current Direct Rendering Manager (DRM) kernel module is available at
dri.sourceforge.net.
The driver supports free modes for Unichrome Pros (K8M800/K8N800, PM800/PN800, and CN400). For plain
Unichromes (CLE266, KM400/KN400), it currently supports only 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
plain Unichromes are currently (in 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 for both 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 "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 downloads
(if DRI is enabled) and for the Render/Composite extension.
Option "ActiveDevice" "string"
Specifies 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" is for laptop
panels (not TFT screens attached to the VGA port), "DFP" is for screens connected to the DVI 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. The DVI port is not properly probed
and needs to be enabled with this option.
Option "AGPMem" "integer"
Sets the amount of AGP memory that is allocated at X server startup. The allocated memory will be
"integer" kB. This AGP memory is used for the AGP command buffer (if the option "EnableAGPDMA" is
set to "true"), for DRI textures, and for the EXA scratch area. The driver will allocate at least
one system page of AGP memory, or -- if the AGP command buffer is used -- at least 2 MB plus 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
the option "MaxDRIMem"). The default amount of AGP is 32768 kB. Note that the AGP aperture set
in the BIOS must be able to accommodate 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 the BIOS.
Option "Center" "boolean"
Enables image centering on DVI displays. The default is disabled.
Option "DisableIRQ" "boolean"
Disables the vertical blank IRQ. This is a workaround for some mainboards that have problems with
IRQs coming from the Unichrome engine. With IRQs disabled, DRI clients have no way to synchronize
their drawing to Vblank. (IRQ is disabled by default on the KM400 and K8M800 chipsets.)
Option "DisableVQ" "boolean"
Disables the use of the virtual command queue. The queue is enabled by default.
Option "EnableAGPDMA" "boolean"
Enables 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. (This option is enabled by default, except on the K8M890 and P4M900.)
Option "ExaNoComposite" "boolean"
If EXA is enabled (using the option "AccelMethod"), this option enables acceleration of
compositing. Since EXA, and in particular its composite acceleration, is still experimental, this
is a way to disable a misbehaving composite acceleration.
Option "ExaScratchSize" "integer"
Sets 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 will slow compositing down. This
option should be set to the size of the largest pixmap used. If you have a screen width of over
1024 pixels and use 24 bpp, set this to 8192. Otherwise you can leave this at the default 4096.
The space will be allocated from AGP memory if available, otherwise from VRAM.
Option "LCDDualEdge" "boolean"
Enables the use of dual-edge mode to set the LCD. The default is disabled.
Option "MaxDRIMem" "integer"
Sets the maximum amount of VRAM memory allocated for DRI clients to "integer" kB. Normally DRI
clients get half the available VRAM size, but in some cases it may make sense to limit this
amount. For example, if you are using a composite manager and you want to give as much memory as
possible to the EXA pixmap storage area.
Option "MigrationHeuristic" "string"
Sets the heuristic for EXA pixmap migration. This is an EXA core option, and starting from Xorg
server version 1.3.0 this defaults to "always". The openchrome driver performs best with
"greedy", so you should really add this option to your configuration file. The third possibility
is "smart".
Option "NoAccel" "boolean"
Disables the use of hardware acceleration. Acceleration is enabled by default.
Option "NoAGPFor2D" "boolean"
Disables the use of AGP DMA for 2D acceleration, even when AGP DMA is enabled. The default 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 when DRI is not enabled.
Option "PanelSize" "string"
Specifies the size (width x height) of the LCD panel attached to the system. The sizes 640x480,
800x600, 1024x768, 1280x1024, and 1400x1050 are supported.
Option "RotationType" "string"
Enabled rotation by using RandR. The driver only support unaccelerated RandR rotations "SWRandR".
Hardware rotations "HWRandR" is currently unimplemented.
Option "Rotate" "string"
Rotates the display either clockwise ("CW"), counterclockwise ("CCW") and upside-down ("UD").
Rotation is only supported unaccelerated. Adding option "Rotate", enables RandR rotation feature.
The RandR allows clients to dynamically change X screens.
Option "ShadowFB" "boolean"
Enables the use of a shadow frame buffer. This is required when rotating the display, but
otherwise defaults to disabled.
Option "SWCursor" "boolean"
Enables the use of a software cursor. The default is disabled: the hardware cursor is used.
Option "TVDeflicker" "integer"
Specifies the deflicker setting for TV output. Valid values are "0", "1", and "2". Here 0 means
no deflicker, 1 means 1:1:1 deflicker, and 2 means 1:2:1 deflicker.
Option "TVDotCrawl" "boolean"
Enables dot-crawl suppression. The default is disabled.
Option "TVOutput" "string"
Specifies 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 is selected via a jumper.
Option "TVPort" "string"
Specifies TV port. The driver currently supports "DVP0", "DVP1", "DFPHigh" and "DFPLow" ports.
Option "TVType" "string"
Specifies TV output format. The driver currently supports "NTSC" and "PAL" timings only.
Option "VBEModes" "boolean"
Enables the use of VBE BIOS calls for setting the display mode. This mimics the behaviour of the
vesa 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. It may not work on 64-bit
systems. Using "VBEModes" may speed up driver acceleration significantly due to a more aggressive
hardware setting, particularly on systems with low memory bandwidth. Your refresh rate may be
limited to 60 Hz on some systems.
Option "VBESaveRestore" "boolean"
Enables the use of VBE BIOS calls for saving and restoring 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 option "VBEModes" is enabled.
Option "VideoRAM" "integer"
Overrides the VideoRAM autodetection. This should never be needed.
TV ENCODERS
Unichromes tend to be paired with several different TV encoders.
VIA Technologies VT1621
Still untested, as no combination with a 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; 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) (available on VT1622 only) provide cleaner TV output (unscaled
with only minimal overscan). These modes are made available by the driver; modelines provided in
xorg.conf will be ignored.
SEE ALSO
Xorg(1), xorg.conf(5), Xserver(1), X(7), EXA(5), Xv(5)
AUTHORS
Authors include: ...