Provided by: xserver-xorg-video-openchrome_0.6.0-5_amd64 bug


       openchrome - video driver for VIA Unichromes


       Section "Device"
         Identifier "devname"
         Driver "openchrome"


       openchrome  is  an Xorg driver for VIA chipsets that have an integrated Unichrome graphics

       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  (
       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

       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.


       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

       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

       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

       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.


       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.


       Xorg(1), xorg.conf(5), Xserver(1), X(7), EXA(5), Xv(5)


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