[PlanetCCRMA] 2.6 kernel; jack, ecasound

Fernando Pablo Lopez-Lezcano nando@ccrma.Stanford.EDU
Fri Aug 27 19:07:00 2004

On Fri, 2004-08-27 at 19:05, Matt Barber wrote:
> I'm using jack a lot with very little trouble.  I'm having only two
> problems:
> 1. If I ever start jack as root, I can not subsequently restart qjackctl
> as a user.  I get no error messages except "Could not connect to JACK
> server as client."  Jackstart and jackd, when started from a shell, just
> hang until I kill them.  Is this common?  Any idea what's causing it, or
> is it perhaps even deliberate?

Nope, it is a bug. Qjackctl is terminating jack rather abruptly and it
does not have a chance to remove the pipes and stuff that it creates in
/var/lib/jack/tmp. Those left over files are owned by the previous owner
and can't be removed by the new one. 

There is a workaround for this problem (thanks to Kjetil) and I have it
working here in a newer version of jack but I have not released it yet. 

> It also looks like ecasound can't talk to jack when jack is in realtime
> mode.  I get this message:
> cannot lock down memory for RT thread (Cannot allocate memory)
> Cannot temporarily set client to RT scheduler: Operation not permitted
> (audioio-jack-manager) Error! Cannot active client!
> Is there a way to allow ecasound to use rt without using sudo?  This is
> for pedagogical purposes, so it's important that we use it in
> conjunction with meterbridge and other jack apps.

Do other jack apps work? 
Which kernel are you using? Are you loading the realcap kernel module?

It would seem that the jack client is not getting the right privileges
from jack to go realtime. 

-- Fernando