Emc vs modern lcd monitors

Felix Miata mrmazda at earthlink.net
Mon Aug 15 15:36:16 PDT 2011

On 2011/08/15 18:16 (GMT-0400) gene heskett composed:

> On Monday, August 15, 2011 06:07:09 PM Alex Deucher did opine:

>>>> gene heskett wrote:

>>  >>  >  One of the problems that was confusing me recently is that I had
>>  >>  >  replaced the old samsung crt monitor with a much newer cheap AOC
>>  >>  >  lcd that runs at 1360x724 at best, but under the vesa driver on an
>>  >>  >  ati x1650 video card, it apparently is running in 1024x768. Â This
>>  >>  >  results in a pixel that is far from square unless I use a button
>>  >>  >  on the monitor which shrinks the display sideways, leaving 2" wide
>>  >>  >  black stripes on the sides.

>>  The problem with vesa is that you are limited to standard vesa modes
>>  that are implemented in the vbios.  You cannot define arbitrary modes.
>>   For that you need to use a real driver specific to your video chip.

> I was afraid of that Alex.  And I tried some Modelines suggested on the EMC
> mailing list&  got thrown under the bus just as it was leaving.  This
> application that must run, is a realtime application with a base loop of
> its i/o running every 20-40 u-secs.  _NO_ "real" driver allows that,
> wrecking carving of parts in wholesale numbers because the IRQ's that drive
> this apps base thread can be locked out by the "real" driver for intervals
> in excess of 100 milliseconds.  The 'vesa' driver is the only driver that
> allows the base thread to keep some semblance of a steady beat.

> This particular card is an ATI X1650.  Does it perchance have an available
> vesa bios update that would add some of the 16x9 modes like this?

If http://en.wikipedia.org/wiki/VESA_BIOS_Extensions#Modes_defined_by_VESA is 
any guide, I'd be really surprised if anyone anywhere found any video card of 
any age that provides BIOS support for the abortion that are the 136Zx7zz 
modes found only in lower cost widescreen desktop displays. If you were to 
spend a bunch of money on lots of video cards you might find something with 
some amount of 16:9 or 16:10 support, but not likely 136Zx7zz would be any of 

I noted the keyword "cheap" above in reference to your new display. If cheap 
is what you're after for your VESA environment, I suggest going back to one 
of the readily available CRTs that are so hard for most people to give away, 
or replace that new widescreen with a new 4:3 LCD display.
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

  Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/

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