[LAU] jackd core dumps in duplex mode

Gerhard Zintel gerhard.zintel at web.de
Sun Aug 2 20:26:21 UTC 2015

Hi list,

I have been running jackd successfully for years now but since some 
time, I can either playback using 
$ /usr/bin/jackd -dalsa -dhw:0 -r44100 -p512 -n2 -P

or capture using
$ /usr/bin/jackd -dalsa -dhw:0 -r44100 -p512 -n2 -C

but trying to use duplex mode
$ /usr/bin/jackd -dalsa -dhw:0 -r44100 -p512 -n2

jackd gives me:
======== snip ==========
jackd 0.122.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben 
Hohn and oth
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.
loading driver ..
apparent rate = 44100
creating alsa driver ... hw:0|hw:0|512|2|44100|0|0|nomon|swmeter|-|
control device hw:0
configuring for 44100Hz, period = 512 frames (11.6 ms), buffer = 2 
ALSA: final selected sample format for capture: 32bit integer 
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 32bit integer 
ALSA: use 2 periods for playback
jackd watchdog: timeout - killing jackd
Aborted (core dumped)
======== snip ==========

in verbose mode I get additionally:
======== snip ==========
new buffer size 512
resizing port buffer segment for type 0, one buffer = 2048 bytes
resizing port buffer segment for type 1, one buffer = 2048 bytes
registered port system:capture_1, offset = 2048
registered port system:capture_2, offset = 4096
registered port system:playback_1, offset = 0
registered port system:playback_2, offset = 0
registered port system:playback_3, offset = 0
registered port system:playback_4, offset = 0
registered port system:playback_5, offset = 0
registered port system:playback_6, offset = 0
++ jack_sort_graph
++ jack_rechain_graph():
-- jack_rechain_graph()
-- jack_sort_graph
346 waiting for signals
======== snip ==========

I have no idea how to proceed from here to find the reason. Any hint 
will be most appreciated.


Further infos:
Audio device: Intel Corporation 7 Series/C210 Series Chipset Family 
High Definition Audio Controller (rev 04)

cat /proc/asound/version
Advanced Linux Sound Architecture Driver Version k3.8.0-35-generic.

cat /proc/asound/cards
gerbil:$ cat /proc/asound/cards
 0 [PCH            ]: HDA-Intel - HDA Intel PCH
                      HDA Intel PCH at 0xf7f10000 irq 44
 1 [Loopback       ]: Loopback - Loopback
                      Loopback 1

cat /proc/version
Linux version 3.8.0-35-generic (buildd at allspice) (gcc version 4.7.3 
(Ubuntu/Linaro 4.7.3-1ubuntu1) ) #50-Ubuntu SMP Tue Dec 3 01:25:33 
UTC 2013

What more on information should I provide?

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