Problems starting in realtime mode

Operation not permitted

By default, Jack starts up in realtime mode. If the user starting jack is not allowed to start realtime processes, the following error might occur:

cannot use real-time scheduling (FIFO at priority 10) [for thread -1210562896, from thread -1210562896] (1: Operation not permitted)

In this case, you might want to set up your limits.conf to allow the audio group access to realtime priorities.

Invalid argument

If you get the following error:

cannot use real-time scheduling (FIFO at priority -4) [for thread -1238631568, from thread -1238631568] (22: Invalid argument)

.. try setting the 'interface' parameter correctly. (see also [http://linuxmusicians.com/viewtopic.php?f=4&t=2588&view=unread#p12107])