Re: OS/2 Warp - Changing Resolutions *DANGER*

["John H. Kim" <jokim@tuna.mit.edu>]

On Fri, 25 Aug 1995, Victor Kress wrote:

> >Connect up a monitor such the the LCD is off. Then from a FULL SCREEN
> >DOS session run "svga on". You will then find under the system setup
> >notebook that other (higher) resolutions are available.
> >
> >Select one and reboot.
> 
> Do not do this if you are using video features disk v.1.33!!!!
> 
> I just did, and scrambled video on my tp750 in a big way.

If you are on a monochrome 750, it is more complicated.  The
status of the video (high-performance or not) makes a big
difference.  I found that if I installed the video drivers
in hi-per mode (i.e. LCD or CRT only, can't do simultaneous),
switching high-performance off scrambled my LCD.  Likewise,
if I installed the drivers with hi-per off, switching it on
scrambled my LCD.  This is a bug in the OS/2 drivers and the
way they interact with the mono LCD.  Apparently there are so
few of us mono OS/2 users that IBM doesn't feel it's worth the
effort to fix this bug (it's been there for over a year).

Note that toggling the hi-per mode will not take effect until
you reboot, and switching hi-per off will disable all SVGA
resolutions on a CRT except 640x480.

Since I almost never needed the simultaneous display but wanted
SVGA on a CRT, I opted to install with high-performance on.
Then the procedure Scott described works beautifully AS LONG
AS YOU DON'T TURN HIGH-PERFORMANCE BACK OFF.

Disclaimer:  I haven't used OS/2 for several weeks so I may be
wrong about the exact details.  I do know for a fact though that
one of the Thinkpad video settings will toggle your mono LCD from
normal to scrambled depending on what mode it was in when you
installed the video drivers.  It took me several reinstalls of
OS/2 and the video drivers to map out exactly when it happens,
and of course I never wrote it down.  :)
___________________________________________________________________________
John H. Kim        "A common mistake that people make when trying to design
jokim@mit.edu       something completely foolproof is to underestimate the
jokim@tuna.mit.edu  ingenuity of complete fools." -- Douglas Adams