[LAU] Very frustrating problem with JACK and exporting through mixbus

Rick Green rtg at aapsc.com
Sun May 13 18:40:09 UTC 2012

On Sun, 13 May 2012, Loris wrote:

> Hi,
> Just wanted to let you know that I also just experienced this exact
> issue with Ardour and a Cakewalk (Roland) UA-25 EX card.. Thanks to
> your messages, I gave a try to jackd v1 and could finally export my
> project. I don't know if it can be related, but that did not ever
> happen with Kubuntu 11.10 and earlier versions (I now run Kubuntu
> 12.04).
   I've been experiencing problems as well when exporting under 
UbuntuStudio 12.04 (kernel 3.2.0-23 & jack2).  In my case, the export 
works fine, but at the end, when ardour tells jack to return to realtime 
mode, I see an error AcquireRealTimeError, and then Ardour freezes up, and 
will not play.  Qjackctl still indicates that jackd is running, but `ps 
aux | grep jack` shows jackdbus, but no jackd.  I have to force-kill 
jackdbus, qjackctl, and ardour and then start over.

   I wonder if it's related to pulseaudio (our recent favorite 
whipping-boy).  UbuntuStudio 12.04's implementation of qjackctl 
automagically makes connections to clients called 'pulseaudio jack source' 
and 'pulseaudio jack sink' whenever you use it to start jackd.  Then when 
you go to stop jack, it throws up a warning about clients still connected. 
I have to go to the 'connections' window, and do a 'disconnect all' before 
stopping jack.  If I simply do a 'stop anyway' in the warning window, I'm 
left in a state where jack won't start again until after a reboot.

Rick Green

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
                                   -Benjamin Franklin

"As for our common defense, we reject as false the choice between our
safety and our ideals."
                                -President Barack Obama 20 Jan 2009

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