[LAD] JACK and computer sleeping

[Fernando Lopez-Lezcano]

On Fri, 2009-03-06 at 19:58 +0100, Jörn Nettingsmeier wrote:
> MarcO'Chapeau wrote:
> > On Thu, 5 Mar 2009 09:07:10 -0500, Paul Davis <paul at linuxaudiosystems.com>
> > wrote:
> >> On Thu, Mar 5, 2009 at 9:02 AM, nescivi <nescivi at gmail.com> wrote:
> >>
> >>> Hiho,
> >>>
> >>> It seems that JACK (just tested with v0.116) does not survive when the
> >>> computer is put to sleep, and woken up again.
> >>>
> >>> Is there any reason why this is so?
> >>
> >> JACK will see this as a major system malfunction. If you are using JACK,
> > do
> >> not let your computer sleep, or suspend, or engage in CPU frequency
> >> scaling.
> >> These all appear to JACK as indistinguishable from your audio interface
> >> ceasing to function in a way that leads it to quit or die. Remember that
> >> JACK is watching the passing of absolute time.
> > 
> > While cpu freq scaling *might* confuse JACK, it seems is not the case here.
> > Sleep is a whole different story...
> 
> for the record, i have not seen problems due to frequency scaling
> either. at least i've switched it off whenever i encountered jack
> problems, and it has never made a difference.

I find that I always have to turn cpu scaling off when I want to do real
jack audio work - unless it is very light load. Otherwise it is bound to
happen that as load changes the cpu slows down, then the cpu load goes
up, perhaps suddenly, and you get xruns. They quickly go away as the cpu
switches speed again - but by then it is too late. 

-- Fernando