[LAD] [Jack-Devel] more jack/qjackctl madness

Rui Nuno Capela rncbc at rncbc.org
Sun May 17 10:48:57 UTC 2009

Stéphane Letz wrote:
>> To whom it may concern: (again)
>> Jackdmp 1.9.2, Qjackctl 0.3.4
>> I do the following:
>> - Log in.
>> - Start a jack app.
>> - The app starts jackd, but using the wrong card,
>>   and things don't work as expected.
>> Questions:
>>  1. Which parameters are used for such an autostart ?
>>     Certainly not the ones in ~/.jackdrc, these would
>>     have been correct.
>>  2. Qjackctl also ignores ~/.jackdrc, so what is the
>>     purpose of this file ?
>> - I terminate the app. Check with ps, there is no
>>   more jackd running.
>> - I start qjackctl. It immediately shows a running
>>   jackd, but his has restarted the previous wrong one.
>> - Click Stop, Start in qjackctl. Get the same wrong
>>   jackd again.
>> - Verify qjackctl's Setup window. This shows the
>>   settings for the right jackd, while it is running
>>   another one.
>> This is *madness*
>> One more: you can't terminate qjackctl without
>> terminating jackd as well. Why not ? Killing
>> qjackctl does the right thing.
>> A request to the jackdmp and qjackctl devs:
>> Ciao,
> Fons,
> I really appreciate your feedback...,  but AFAICS Qjackctl is
> *absolutely* not using the DBUS layer!
> With jackdmp/jack2 compiled with default settings (that is *not* using
> the --dbus at configure step), then it should absolutely behave as jack1
> was behaving.
> And I guess Rui can better answer the points concerning "~/.jackdrc,"
> and son on.

qjackctl only writes to ~/.jackdrc *iif* you opt to (see Setup/Misc/Save
JACK audio server configuration). otherwise it *never* makes use of that
file ie. it never auto-starts jackd implicitly; it only does start jackd
explicitly if none is found running atm.

if you really want several jackd server running simultaneously you'll
have to take use of the JACK_DEFAULT_SERVER environment variable to tell
qjackctl which server it will refer to. in fact, that is the only tricky
way for you to have several qjackctl instances running as well.

Stephane is right, qjackctl makes no use of the d-bus interface in
jackaudio.org domain, although the latest in qjackctl cvs has some d-bus
stuff of its own (rncbc.org domain) and only serves for
starting/stopping qjackctl control--found useful for example to any
system suspend/resume script you may think of.

otoh, the only other jack application i know of that writes to
~/.jackdrc is ardour; have a look at your use case when starting jackd
from behind ardour's open session dialog...

rncbc aka Rui Nuno Capela
rncbc at rncbc.org

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