Re: precise timing control of double-buffering flip

[Paul Davis <paul linuxaudiosystems com>]

On Mon, 2006-12-11 at 16:52 +0100, Fabrice Pardo wrote:
> Paul Davis wrote:
> > On Mon, 2006-12-11 at 12:22 +0100, Fabrice Pardo wrote:
> >   
> >> Hello,
> >>
> >> I'm searching a way to ask the time of double-buffering flip.
> >> In order to make a kind of oscilloscope.
> >>     
> >
> > what do you think the refresh rate of your screen is?
> >   
> Something between 10ms and 20ms. Why ? Is-it possible
> to predict the hardware next refresh time ?

if you use OpenGL with the right options, you don't have to predict it,
you can get the vertical retrace interrupt to drive screen updates.
without this, any attempt to precisely sync screen updates is likely to
regularly do the wrong thing and produce visible glitches.

--p