From: ochealth@unixg.ubc.ca (ochealth)
Subject: Trident SVGA: some partial solutions
Organization: University of British Columbia, Vancouver, B.C., Canada
Date: Sat, 15 Aug 1992 19:42:39 GMT

Well, I don't wish problems on people, but I'm glad I'm not the only one
with similar problems! Maybe they'll be a WORKING Fix. Fortunately, Trident
has released several patches, it's just that they dont fix everything 100%

This is: Trident SVGA 8900C. Running with OS/2 PM SVGA drivers (800x600,
1024x768)

Heres a summary of problems, and a few workarounds (where I've found them)

1. Switching from from DOS or WinOS/2 full screen back to a OS/2 PM screws up
   the PM desktop. May happen when swithcing from a full screen OS/2 as well.

   Fix:
   Get the Trident patch program. Backup your display.dll, and run the patch
   on it. The solution works, but is a kludge: it forces a total re-draw of
   the screen, which is slower than switching video pages, which is almost
   instantaneous.

2. Switching from OS/2 PM to a full screen DOS Text or Graphics screen causes
   loss of sync in the Text screen, and a weird graphics mode for the graphics
   session (sometime multiple images/mouse cursors etc).

   Sort of Fix:
   The other Trident vsvga/vvga stuff should have corrected this but it doesn't
   really work all the time. Example: for the longest time, I had the Trident
   working beautifully, but then a change of video mode and SVGA ON trashed it.
   My setup hasn't been the same since.

   Try running the modetest program that comes with the Trident card in a
   FULL SCREEN DOS session. Set the video mode to whatever the OS/2 desktop
   is: ie if your OS/2 is 1024x768, 256 color, set the DOS mode to this
   (mode 62h by the way), then run SVGA ON. It probably won't change
   svgadata.pmi, so I don't know why this works (sometimes). Exit and reboot.
  
   See if it helps. If it doesn't, try again 1 or 2 time; or try some 
   different video modes. If this doesn't help, and you have ALL the other
   Trident 8900C patches, then you are S.O.L.

   Alternate technique: repeat the above: setting DOS into graphics mode,
   SVGA ON, then type SVGA ON again. Or run modetest again, and set it to
   the DOS TEXT mode you are using; then run SVGA ON; exit and reboot etc.

   If you get your DOS working again, don't be surprised if it has a relapse!
   Windows or certain weird video modes *may* trigger a relapse. I think the
   SVGADATA.PMI file is bogus. Somehow the video system gets altered, even 
   though the SVGADATA.PMI hasn't changed. It's like it gets stored somewhere
   else...vooodoo!

3. Swithcing from Full screen WinOS2 back to OS/2 PM changes the video pallete.
   The result is that the screen looks intact, but the colors are weird
   (strange pastel colors from hell, weird oranges and green and purples).

   Workaround: No permanent fix. just start a DOS or OS/2 full screen session
   then switch back, the PM screen should be OK now.

   I've never seen anyone mention this problem before. Maybe it's just me
   (I'm running Rommels screen blanker, which messes with the pallete registers.
   MAYBE that's causing something, but that's only a guess)


4. Incompatibility with certain graphics modes (namely Ultima Underworld)
   Basically, none of the tricks posted before help UW on a Trident. I have
   It works with the standard VGA drivers. *Once* I got it working, but I've
   never duplicated this feat. I get weird graphics with UW: stuff smeared all
   over the place, you can sort of see what the screen looks like. Am I the only
   one with this problem? anyway, I think *both* Trident and IBM have bugs in
   their video code.
 
   Fix: none.

This sums up the Trident problems I've found. I sent E-mail to Trident
but they never responded.






-- 
______________________________________________________________________________
jpm: ochealth@unixg.ubc.ca         
                            Happily using OS/2 2.0 because MS Windows isNT ___
                                                      Insert VapourFeature ^^^
From: kevinl@tisdec.tis.tandy.com
Date: 18 Aug 92 12:10 CDT
Newsgroups: comp.os.os2.misc
Subject: Re: Orphaned Response
Message-ID: <13000004@tisdec.tis.tandy.com>