xenocara/driver/xf86-video-rendition/README

  Information for Rendition (Micron) Verite Users
  The XFree86 Project Inc.
  9 June 2000, last update by Dejan Ilic "dejan.ilic@home.se"
  ____________________________________________________________

  Table of Contents


  1. Supported hardware
  2. Limitations
  3. Important notices
  4. Features
  5. xorg.conf Option
  6. News in the X11R7.5 release
  7. News in the XFree86 4.1 release
  8. Major changes in this release
  9. Bugfixes
  10. Known problems in current driver
  11. Work in progress (not finished in time for release)


  ______________________________________________________________________

  1.  Supported hardware

  All cards based on the V1000 or the V2x00 should be supported. The
  server was tested on a miroCRYSTAL VRX (V1000), Intergraph Intense-100
  3D (V1000), Diamond Stealth II S220 (V2100), Hercules Thriller3D
  (V2200), Innovision Warrior3D (V2200) and Genoa V-Raptor (v2200).


  2.  Limitations

  V1000 cards can only work as primary display card due to hardware
  limitations.

  V2x00 cards can work even if not primary, but primary display card
  will be disabled when server is run. This is a driver limitation.

  Hopefully these limitations were worked around and fixed before final
  XFree86 4.0 release.



  3.  Important notices

  Some V1000-based video cards are known to lock up the computer if you
  have write-combine activated. Disabling it removes the problem. Look
  for settings in the motherboards BIOS and disable ALL settings that
  has to do with write-combine (usually called USWC or just WC for
  short).


  15 bits per pixel is only supported on V1000-based cards due to
  hardware limitations on V2x00 chipsets.


  If you have problems with hardware cursor use the "sw_cursor" option
  to revert back to software cursor.


  This is essentially a port of XFree86 3.3.x driver to the new XFree86
  4.0 API, and thus we have put most of effort in making a working
  driver with the most basic features. Support for multi-head support
  and acceleration are next on the list of features to be included.

  4.  Features


  o  Hardware acceleration

  o  Hardware cursor

  o  Supported color depths

     o  8 bits per pixel (256 pseudo colour)

     o  15 bits per pixel (actually 16-bits with RGB-weight 555, 32768
        colors)

     o  16 bits per pixel (high colour, RGB-weight 565, 65536 colors)

     o  32 bits per pixel (true colour, sparse 24bit, 16M colors)


  5.  xorg.conf Option


     Option
        Disables use of the hardware cursor.

     Option
        Run the memory at a higher clock. Useful on some cards with
        display glitches at higher resolutions. But adds the risk to
        damage the hardware. Use with caution.

     DacSpeed
        Set custom ramdac limit. We have currently no way of knowing if
        the v2x00 chip is a v2100 (170MHz) or v2200 (203MHz and 230MHz)
        so we assume the lowest. Use this option to manually override
        the value.

     Option
        If writecombine is disabled in BIOS, and you add this option in
        configuration file, then the driver will try to request
        writecombined access to the framebuffer. This can drastically
        increase the performance on unaccelerated server. Requires that
        "MTRR"-support is compiled into the OS-kernel.

     Option
        Disable probing of DDC-information from your monitor. This
        information is not used yet and is only there for informational
        purposes. This might have changed before final XFree86 4.0
        release. Safe to disable if you experience problems during
        startup of X-server.

     Option
        If this option is enabled, the driver will cause the CPU to do
        each drawing operation first into a shadow frame buffer in
        system virtual memory and then copy the result into video
        memory.  If this option is not active, the CPU will draw
        directly into video memory.  Enabling this option is beneficial
        for those systems where reading from video memory is, on
        average, slower than the corresponding read/modify/write
        operation in system virtual memory.  This is normally the case
        for PCI or AGP adapters, and, so, this option is enabled by
        default unless acceleration is enabled.

     Option
        The option expect a value "CW" for clockwise or "CCW" for
        counterclockwise rotation of the screen. This is useful when you
        need more height then width on the screen. Desktop publishing is
        one example where a monitor could display the whole page at once
        on a monitor laying on the side.  Notice that this option
        requires "ShadowFB" and automatically enable it. It also
        disables the acceleration.  The option is not activated by
        default.


  6.  News in the X11R7.5 release

  This driver was originally part of the XFree86 4.4 rc2 release.


  7.  News in the XFree86 4.1 release


  o  DirectColor support

  o  SilkenMouse support


  8.  Major changes in this release


  o  Gamma works now for >8bpp


  9.  Bugfixes


  o  Only some code cleanup done. No real bugfixes.


  10.  Known problems in current driver


  o  The acceleration code hangs the computer during X-server startup.

  o  DDC-probing does not work correctly yet. No DDC information is
     found.

  o  Switching from display to VC and back to display can lock up V2x00
     cards.

  o  When scrolling the virtual display on a V1000 card parts of the
     screen will become distorted. Problem disappears when you continue
     moving around. V2x00 does not exhibit this problem. Probably a bug
     in the driver rather than a limitation of the chip.

  o  Depth 15 & 16 has problems with colors when DirectColor is used.


  11.  Work in progress (not finished in time for release)


  o  Acceleration is disabled for the moment. If you want to play with
     it enable the "USE_ACCEL" define in rendition.c file! Beware as it
     has several bugs left to clear out before if is stable for general
     use.