[Bug 42035] no way to turn off vsync

[Michal Suchanek]

2011/10/24 Michel Dänzer <michel at daenzer.net>:
> On Mon, 2011-10-24 at 16:25 +0200, Michal Suchanek wrote:
>> 2011/10/24 Michel Dänzer <michel at daenzer.net>:
>> > On Mon, 2011-10-24 at 14:00 +0200, Michal Suchanek wrote:

>> I am asking this because my experiments with glxgears  without the
>> patch show vrefresh limited fps, fps unlimited by vrefresh, and 0 fps
>> depending on some variables like what screen the window is on, if the
>> window is mapped or not,
>
> Sounds like issues with determining which CRTC to synchronize to.
>
>> if the screen is blanked or not,
>
> As you discovered recently, the hardware CRTCs only generate vertical
> blank interrupts while they're enabled.
>
>> and current phase of the Moon or some other variable I can't figure out.
>
> It's certainly nothing to do with the phase of the moon. :)

I wonder what is it what determines if the application runs uncapped
or gets stuck in some GL call when the crtc is turned off.

One week it would consistently stop applications on turning the crtcs
off, another it would consistently run them uncapped.

Without restarting the X server, no less.

>
> Not sure what any of that has to do with this patch though.

With this patch it should be at least possible to turn off all this
when it does not work.

Thanks

Michal