Re: [Jack-Devel] ALSA PCM multi plugin and xruns

On Tue, Dec 11, 2012 at 10:05:40AM -0800, Devin Anderson wrote:
> Hi John,
> 
> On Tue, Dec 11, 2012 at 8:28 AM, John Rigg <[hidden]> wrote:
> 
> > When jackd detected no xruns it produced this message repeatedly:
> > snd_pcm_multi_avail_update: sync issue: 1025 1024
> >
> > When jackd detected xruns it produced this message:
> > snd_pcm_multi_avail_update: sync issue: 1024 0
> > There appeared to be two of these messages for every xrun
> > indication.
> >
> > Does this make sense?
> 
> Yes, that makes sense.
> 
> I'm guessing that the first device in your .asoundrc uses internal
> sync, and the second device listed in your .asoundrc is synced to the
> first device via word clock.  If that's the case, then I'd like you to
> try setting the 'master' device in your multi device to the second
> card.  You can do this using the 'master' parameter in the pcm 'multi'
> section of your .asoundrc:
> 
>     pcm.some_name {
>         [... the parameters you already have]
>         master 1;
>     }

The second card is synced to the first via S/PDIF. My .asoundrc
doesn't contain a master parameter, but does have

ctl.capture16{
	type hw
	card 0
}

and a similar entry for the playback device. The ice1712 chip has 12
inputs and 10 outputs, so separate capture and playback devices have
to be configured. My full .asoundrc is shown here:
http://www.jrigg.co.uk/linuxaudio/ice1712multi.html

I just tried changing the ctl parameters to use card 1 and the messages
from pcm_multi are the same as before. BTW on my main system with
3 x ice1712 cards there's a common clock supplying all three cards
simultaneously. It also shows the same xrun messages from jackd when
using pcm_multi. It would be interesting to see what the extra fprintfs
in pcm_multi.c would show on that system.

John

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