Re: [LAU] Ubuntu 18.04 can't stop Jack from qjackctl

"The problem (feature) with the debian jackd2 install of both jackd
and jackdbus, is that if jack is not running and the user starts an
application looking for jack, it will start jackd for them by default.
then qjackctl will not be able to run jackdbus as normal."

I have qjackctl as one of my Startup Applications, starts minimised to Tray but is always running well before I could even consider opening an audio application so this definitely isn't my issues. I've always worked like this.

I didn't think you could change devices, or generally get any of the Settings you change to take affect, without Stopping and Starting the Jack Server again. Not actually really tested it though. I have two saved configs, one for my internal audio, one for my external interface. I'd usually - Stop, open Settings, select other Config, OK, Start - and everything would be good. Now it hangs when I hit Stop, or if it doesn't and looks to have stopped I don't believe it really has as I did a test and still got unbroken sound, which I know usually dies if I Stop Jack while something is playing through it.

I've tried with the d-bus settings both enabled and disabled with no overall joy but have to admit I've always been confused into exactly what affect these really have on the system....

Dale.
________________________________
From: Linux-audio-user <linux-audio-user-bounces@email-addr-hidden> on behalf of Len Ovens <len@email-addr-hidden>
Sent: 07 July 2018 16:32
To: linux-audio-user
Subject: Re: [LAU] Ubuntu 18.04 can't stop Jack from qjackctl

On Sat, 7 Jul 2018, Dale Powell wrote:

> Thanks for pointing out jack_control, I should have searched that first rather
> than brute forcing it with the ugly commands I know.

jackdbus, as I understand things, if a wrapper around jackd. It is
however, very tightly coupled because it can do things like change the
master device or sample rate (don't do that) without stopping jack. It may
be that qjackctl is using this ability when you change devices. I have
found that I can plugin a USB device and switch master to that device
without stopping jack and most connections (except to system*) stay
connetced and the clients don't notice anything. However that only seems
to work once, trying to switch master twice (back to internal so I can
pull the plug) seems to freeze jackdbus.

certainly pulling the plug while jack is using a USB device has always
been a problem for me though I know of others who have been able change
master even after unplugging the device.

I do not recall having this problem in the past. Something to look at in
the code to see what is different from jackd 1.9.11 and 1.9.12.

> package, not something that has always been like this on 18.04 for me. When did
> you last do an apt upgrade?

apt update shows: "All packages are up to date."

--
Len Ovens
www.ovenwerks.net<http://www.ovenwerks.net>
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Received on Sat Jul 7 20:15:07 2018