As I remember, under MS-DOG the standard practice is to wait until
just after vertical retrace. Then you have the whole frame to update
the register. I guess this would be unacceptable under Linux, because
most video cards don't generate a vertical interrupt and polling would
steal CPU from more interesting tasks.
>From the other hand, using SVGATextMode to set 100MHz refresh rate will
make flicker much less likely :)
>
> Unfortunately, there is no easy way to tell when it's safe to
> reprogram the video card registers, so the penalty for very fast
> screen update is occasional flickers of glitch. I think it's
> a worthwhile tradeoff, myself.
-- _. _ . (_ ,_ _ , . / ` _ _L | Email: Oleg Kibirev <snowcat@netgate.net> ._)| U(_)\/\/ \_,(_L/L | Visit http://math.math.CSUFresno.EDU/~oleg/math.html ------------------------' to get my programs + PGP public key