Messages in this thread |  | | From | Snow Cat <> | Subject | Re: SMALL bug | Date | Sat, 26 Oct 1996 01:33:58 -0700 (PDT) |
| |
Colin Plumb once wrote: > > The problem is that programming the hardware is not atomic (it takes > several steps) and if the video hardware starts to display a screen > while the programming is halfway complete, it will take half of the old > pointer, half of the new pointer, and put them together to make > something bizarre which it will then display for 1/60 of a second. >
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
|  |