[Jackit-devel] [linux-audio-user] pam modules / non root users can't get realtime privileges.

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Sun Feb 4 19:54:01 EST 2007


On Sun, 2007-02-04 at 20:49 +0100, Marcos Guglielmetti wrote:
> El Lun 05 Feb 2007 00:25, Fernando Lopez-Lezcano escribió:
> > On Sat, 2007-02-03 at 17:24 +0100, Marcos Guglielmetti wrote:
> > > El Sáb 03 Feb 2007 21:13, Ken Restivo escribió:
> > > > On Sat, Feb 03, 2007 at 04:48:31PM +0100, Marcos Guglielmetti wrote:
> > > > > What is happening? see:
> > > > >
> > > > > jackd -v -p128 -t2000 -m -dalsa -dhw:0 -r48000 -p512 -n2 -s -S -H
> > > >
> > > > Did you forget the "-R" flag to make jackd run in realtime?
> > >
> > > Ouch, yes sorry, I was testing how does it goes without realtime, but.
> > >
> > > Now, I did it Ok, and the problems are still here: no realtime, too much
> > > xruns:
> > >
> > > jackd -R -v -p128 -t2000 -m -dalsa -dhw:0 -r48000 -p512 -n2 -s -S -H
> > >
> > > getting driver descriptor from /usr/lib/libjack0.100.0-0/jack_dummy.so
> > > getting driver descriptor from /usr/lib/libjack0.100.0-0/jack_oss.so
> > > getting driver descriptor from /usr/lib/libjack0.100.0-0/jack_alsa.so
> > > jackd 0.101.1
> > > Copyright 2001-2005 Paul Davis and others.
> > > jackd comes with ABSOLUTELY NO WARRANTY
> > > This is free software, and you are welcome to redistribute it
> > > under certain conditions; see the file COPYING for details
> > >
> > > JACK compiled with System V SHM support.
> > > server `default' registered
> > > loading driver ..
> > > registered builtin port type 32 bit float mono audio
> > > required capabilities not available
> > > capabilities: =
> >
> > Hmmm, this does not sound right.
> >
> > Capabilities was an old hack to get things running as non-root with
> > 2.4.x kernels (and the jackstart suid program). What options are you
> > building jack with? You don't need to / should not enable capabilities.
> 
> apt-cache policy jackd
> jackd:
>   Instalados: 0.101.1-2
>   Candidato: 0.101.1-2
>   Tabla de versión:
>  *** 0.101.1-2 0
>         990 ftp://ftp.fr.debian.org testing/main Packages
> 
> 
> I am not building jack, as you can see: I preffer to use the Debian builded 
> versions
> [MUNCH]
> Ok, so you think that the problem could be into the Debian package?

It looks likely but Debian users should know and be able to answer. 

It looks like the package was built to use capabilities. I don't know
what jackd does when it does not find the proper capabilities (which
will not be found if you are using pam), whether it still tries to get
SCHED_FIFO or if it just gives up, it looks like the later. 

-- Fernando





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