[proaudio] jackd refuses realtime - it used to work?

[Johan Ekenberg <johan@xxxxxxxxxxx>]

Hi!

Using 2.6.19-rt15, realtime-lsm and jack 0.102.20, I did a lot of audio programming a few months back. Now I'm trying to continue where I left off, but jackd refuses to run with -R.

===
johan@duo:~$ jackd -v -R -d alsa
getting driver descriptor from /usr/lib/jack/jack_portaudio.so
getting driver descriptor from /usr/lib/jack/jack_dummy.so
getting driver descriptor from /usr/lib/jack/jack_oss.so
getting driver descriptor from /usr/lib/jack/jack_alsa.so
jackd 0.102.20
JACK compiled with System V SHM support.
server `default' registered
loading driver ..
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
control device hw:0
configuring for 48000Hz, period = 1024 frames, buffer = 2 periods
ALSA: final selected sample format for capture: 32bit little-endian
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 32bit little-endian
ALSA: use 2 periods for playback
registered builtin port type 32 bit float mono audio
registered builtin port type 8 bit raw midi
clock source = system clock via gettimeofday
required capabilities not available
capabilities: = cap_ipc_lock,cap_sys_nice,cap_sys_resource+e
new client: alsa_pcm, id = 1 type 1 @ 0x805aee0 fd = -1
new buffer size 1024
registered port alsa_pcm:capture_1, offset = 4096
registered port alsa_pcm:capture_2, offset = 8192
registered port alsa_pcm:playback_1, offset = 0
registered port alsa_pcm:playback_2, offset = 0
++ jack_rechain_graph():
client alsa_pcm: internal client, execution_order=0.
-- jack_rechain_graph()
23315 waiting for signals
  ==>  <here is a ~5 second delay>
jackd watchdog: timeout - killing jackd
Aborted
===

"required capabilities not available"? 
realtime-lsm is loaded, it's the same kernel and jackd as before. I'm in the audio-group as always.

When running as root, it also stops after "waiting for signals":
===
root@duo:/home/johan# jackd -v -R -d alsa
  < the same as above until: >
running with uid=0 and euid=0, will not try to use capabilites
  < again as above until: >
8107 waiting for signals
  ==> <again the ~5 second delay>
jackd watchdog: timeout - killing jackd
Aborted
===

Yes, audio using ALSA still works normally. The hardware has not changed. The system is configured according to http://proaudio.tuxfamily.org/wiki/index.php?title=Realtime_%28RT%29_Kernel

I never actively tried to use PAM/RLIMITS, but I see that /etc/security/limits.conf has:
# REALTIME support for audio group users
@audio          -       rtprio          100
@audio          -       nice            -10
@audio          -       memlock         250000

Could this be causing a conflict with realtime-lsm? I tried rmmod realtime and jackd -R but no improvement.

Running jackd without -R "works", given very high latency settings. With -R I used to run with 4-7 msec latency with few or no xruns.

How can I find the cause of this problem? Surely, something on the system must have changed over time, through the regular "emerge -Duv world + revdep-rebuild" cycle - but what??

I'm a bit desperate for help - right now I can't use jack at all...

/Johan Ekenberg - Sweden