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OPENCHROME(4)              Kernel Interfaces Manual              OPENCHROME(4)



NAME
       openchrome - video driver for VIA Unichromes

SYNOPSIS
       Section "Device"
         Identifier "string"
         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,   CN400,  CN700,  K8M800/K8N800,  PM800/PN800,  P4M800Pro,
       VN800, PM880, K8M890/K8N890, CN896,  VN896,  and  P4M900.   The  driver
       includes  2D acceleration and Xv video overlay extensions.  Flat panel,
       TV, and VGA outputs are supported, depending on the hardware configura-
       tion.

       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() 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.  Con-
              trary to XAA, EXA implements acceleration for screen uploads and
              downlads (if DRI is enabled) and for the Render/Composite exten-
              sion.

       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 accomodate the amount of AGP
              memory specified here.  Otherwise no AGP memory will  be  avail-
              able.  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 dis-
              abled.

       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 particu-
              lar 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, other-
              wise 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  configu-
              ration  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, 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 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 "Rotate"  "string"
              Rotates the display either clockwise ("CW") or  counterclockwise
              ("CCW").  Rotation is only supported unaccelerated.

       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 "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 "VBE-
              Modes" 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;  mode-
              lines 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) (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(), xorg.conf(), xorgconfig(), Xserver(), X()

AUTHORS
       Authors include: ...



X Version 11             xf86-video-openchrome 0.2.902           OPENCHROME(4)