  README.VIDEO7
  Craig Struble
  17 May 1994

  1.  The Driver:

  The Video7 driver has only been tested on a Headland Technologies
  HT216-32 chip, but should work on other Video 7/Headland Technologies
  chips as well.


  Currently this implementation of the video7 driver only supports
  single bank mode, which can cause performance degradation, and makes
  no attempt to distinguish between the different video7 chips.


  It also does not probe for memory, so in your XF86Config file, make
  sure that you use the following line:


          Videoram XXX


  Where XXX is the amount of RAM in your card. Most of them have at
  least 512k, so this is a good value to start with.

  Also, the clock probing function of XFree86 doesn't seem to correctly
  get the clocks. The documentation I used (vgadoc3) suggests using the
  following values for the Clocks line in your XF86Config file:

          Clocks        25.175 28.322 30.000 32.514 34.000 36.000 38.000 40.000


  For 800x600 mode, use a dot clock of 38 instead of 36 or 40 as sug-
  gested in most of the sample XF86Config files and modeDB.txt.  This
  seems to be what is used in the BIOS mode (0x69) which is the 800x600
  in 256 colors.


  2.  Known bugs and What's been tested:


  2.1.  Known bugs:


     1. No video ram probing. Only known way to get this info is through
        an INT 10 call, but you can't do this in a user process.


     2. Clock probing. I'm not sure the docs in vgadoc3 are correct.


     3. Random lockups with the SVGA server


  2.2.  What's been tested:


     1. An HT216-32 chip.


     2. 800x600 mode and 640x480 mode


     3. Mode switching and switching to text mode through CTRL-ALT-F1

     4. Only been tested on Linux.



  3.  Who to contact:

  Craig Struble (cstruble@acm.vt.edu) Video 7 driver


  4.  Acknowledgments


  4.1.  Thanks to:


     o  Cara Cocking for loving me and supporting me. Without her I'd be
        a bowl of jello.


     o  XFree86 team for the great stub code that allowed me to get this
        going.


     o  Finn Thoegersen for compiling vgadoc3. Without this I would not
        have had a clue.


     o  Harm Hanemaayer for the vga.c program in svgalib. Without this I
        would not have had the breakthroughs I needed to get the thing
        up and running.


  4.2.  Other things I've already done:


       For Linux, I have a small patch to get the extended text
       modes to work on the Video 7 card.




  4.3.  Things to do:


     o  Try dual banking mode.


     o  Write an svgalib driver.


     o  Go back to graduate school. (I'm a glutton for punishment.)



  4.4.  Disclaimer:


       CRAIG STRUBLE DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
       SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABIL-
       ITY AND FITNESS. IN NO EVENT SHALL CRAIG STRUBLE BE LIABLE
       FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
       DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROF-
       ITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
       TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
       USE OR PERFORMANCE OF THIS SOFTWARE.

  $XConsortium: Video7.sgml,v 1.1 95/01/06 20:29:55 kaleb Exp $
  Generated from XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/Video7.sgml,v 3.2 1995/01/28 16:02:44 dawes Exp $
































































