Excerpts from fons's message of 2010-04-07 00:46:09 +0200:
It seems like Arch is currently offering Jack and qjackctl packages that are not compatible.
The Jack authors changed one some command line options in 0.118. '-R' for realtime is no longer available as realtime is now the default, and the new '-r' means 'no realtime'.
Qjackctl 0.3.6 is aware of this, but won't work well with Jack 0.116 which is still the one available from Arch. In other words, the update of qjackctl was probably a bit premature.
Ciao,
The real problem is that jack is still stuck at the rather old 0.116. One reason might be those, IMHO in the meanwhile annoying scripts that ship with the Arch jack package. It's tough to get them right it seems. I would be all in favor of splitting them into a separate package and install jack just the way it is supposed to. Much less hassle, less confused users and as a bonus those scripts can be easily used with other variants of jack. Either way, there's really no reason to still ship 0.116.2 when 0.118.0 was released in November, almost 5 months ago.