[Jack-Devel] Jack on Raspberry PI 2 (Ron)

Jörn Nettingsmeier nettings at stackingdwarves.net
Mon Apr 20 12:39:26 CEST 2015

On 04/17/2015 02:13 PM, Jeremy Jongepier wrote:

>> BUT if I start jackd via a terminal session (cygwin terminal) and enter:
>> /usr/local/bin/jackd -r -dalsa -dhw:0 -r48000 -p1024 -n2
>> jackd responses with:
>> ron at squireoaksfarm-radio ~/Desktop $ /usr/local/bin/jackd -r -dalsa
>> -dhw:0 -r48000 -p1024 -n2
>> jackdmp 1.9.11
>> Copyright 2001-2005 Paul Davis and others.
>> Copyright 2004-2014 Grame.
>> jackdmp 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 server starting in non-realtime mode
>> creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
>> control device hw:0
>> ALSA: Cannot open PCM device alsa_pcm for capture. Falling back to
>> playback-only mode
>> configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
>> ALSA: final selected sample format for playback: 16bit little-endian
>> ALSA: use 2 periods for playback
>> As you can see the jackd server does NOT report  can not lock memory.
>> Why is this?
> Not sure, maybe because the desktop consumes a lot of memory.

I don't know how these things work on ARM systems, but if you 
reconfigure your realtime and memlock permissions (via 
/etc/security/limits.conf on usual systems), these changes will not 
affect the current session but require a re-login. This might explain 
why it's not working in the graphical environment (with a persistant 
session), and it does work on a new terminal.
Have you tried restarting the graphical session?

Jörn Nettingsmeier
Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487

Meister für Veranstaltungstechnik (Bühne/Studio)
Tonmeister VDT


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