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       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 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
       and  VX855.   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

       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() 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" 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 "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

       Option "Center"  "boolean"
              Enables  image  centering  on  DVI  displays.   The  default  is

       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  on  Xorg  server  versions  after 1.1.0 this
              defaults to "smart".  The openchrome driver performs  best  with
              "greedy",   so  you  should  really  add  this  option  to  your
              configuration file.  The third possibility  is  "always",  which
              might become more useful in the future.

       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 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


       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(), xorg.conf(), Xserver(), X()


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