[LAD] [Jack-Devel] more jack/qjackctl madness : some comments

Stéphane Letz letz at grame.fr
Sun May 17 18:04:54 UTC 2009

Le 17 mai 09 à 19:57, Paul Davis a écrit :

> On Sun, May 17, 2009 at 1:49 PM, Stéphane Letz <letz at grame.fr> wrote:
>> After all these discussions on JACK2, D-Bus and Qjackctl issues,  
>> here are
>> some general comments:
>> 1) JACK2 *default* compilation mode defines the same starting  
>> scheme at
>> JACK1 was doing. So (beside possible bugs) it is supposed to be  
>> completely
>> "interchangeable" with JACK1. It can be controled with Qjackctl as  
>> usual.
>> 2) JACK2 compiled in D-Bus is supposed to be controlled by a D-Bus  
>> based
>> control application... (jack_control is a simple python example of  
>> a control
>> application part of the package). Using JACK2 compiled in D-Bus with
>> Qjackctl is a "receipe for trouble", even if if can be done in  
>> some simple
>> use cases. (The point is that in this case the client auto-start  
>> feature
>> starts the "jackdbus" exe instead of "jackd" with all of the related
>> "settings" issues).
>> 3) The port issue Fons told about in Qjackctl  0.3.4 seems to be a  
>> Qjackctl
>> bug, so has to be fixed at the right place.
>> I don't see right now any raisonable way to fix this mess, better  
>> than
>> adding even more complexity in the design... (Nedko any idea?)  
>> Otherwise I
>> guess the only way is to make this totally clear for packagers :   
>> 1) is the
>> standard way that maintains complete compatibility with legacy  
>> applications
>> and control applications. 2) is the "new" way to be used with new  
>> D-Bus
>> based control application (patchage ??)...  So it would mean 2   
>> separated
>> packages.
> this sounds like a mess. there is a control API. i believe it was
> agreed that the control API could be accessed directly (from C/C++
> etc), or via other systems for which translators/layers were added
> (e.g. DBus). i can see no reason why anyone would want to use choose
> between a JACK server that can be controlled via either DBus or the
> control API but not both. what is going on?

The point is that when compiled in D-Bus mode, libjack behaves  
differently regarding the way it start the server: it does not use  
the fork+exec mode anymore but call the D-Bus service to start the  
server. This "simple" change is the source of all the problems we  
then see.


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