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

[Len Ovens]

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