F13+: Has anyone been able to get jackd to run with pulseaudio?

Daniel B. Thurman dant at cdkkt.com
Sun May 22 02:44:42 UTC 2011

On 05/21/2011 04:20 PM, JD wrote:
> On 05/21/11 15:03, Daniel B. Thurman wrote:
>> I searched everywhere on the Internet and found
>> lots of people complaining that PCM could not be
>> opened, thus terminating jackd.
>> Here is what I an getting from starting jackd via qjackctl:
>> $ jackd -d alsa
>> jackd 0.118.0
>> Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
>> 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
>> Memory locking is unlimited - this is dangerous. You should probably
>> alter the line:
>>       @audio   -  memlock    unlimited
>> in your /etc/limits.conf to read:
>>       @audio   -  memlock    1540245
>> JACK compiled with System V SHM support.
>> loading driver ..
>> 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 playback. Falling back to
>> capture-only mode
>> configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
>> ALSA: final selected sample format for capture: 16bit little-endian
>> ALSA: use 2 periods for capture
>> impossible sample width (1) discovered!
>> I have tried everything, including the kitchen sink and cannot
>> seem to get jackd running.
> I had tried some months ago.
> I gave up because it ended up screwing up my audio
> so I could no longer get sound out.
The hard part is finding a site that tells you step-by-step
what exactly needs to be done.  I had to cobble bits
and pieces together from different Internet postings to get
it to work, as many are for older versions of jack and/or
pulseaudio and for different distros - so I used Ubuntu/Fedora
distros to assemble it specifically for F13.

>From memory, I recall:
1) yum install pulseaudio-module-jack alsa-plugins-jack
2) Add the user to audio, jackuser, pulse, pulse-access
3) echo "autospawn = no" > ~/.pulse/client.conf
4) cp /etc/pulse/default.pa ~/.pulse/pulsejack.pa
    Edit and add after the below commented out line:
   #load-module module-pipe-sink
    load-module module-jack-source
    load-module module-jack-sink
5) reboot

Sorry that I cannot locate the specific links where
I found all of the pieces...

But once the basic configuration is done for both
jack and pulse audio, then one can proceed to use
qjackctl tool.

See: https://help.ubuntu.com/community/HowToJACKConfiguration

I found that jack has to be "tuned" to make sure
that there is the proper latency settings (mine is
@ ~25ms, and you can easily do this with the jack
tool: qjackctl and keeping an eye on minimizing
the Xruns, which determines the "optimal" latency
setting for your system.

I have tried Hydrogen, MuseScore, Rosegarden and
these seem to work well.  For fun. I had Amarok
running and at the same time Hydrogen Jazz drums
running and it was odd, but interesting.

Some notes:
1) Be careful not to checkbox the qjackctl->Misc:"Start
    jack audioserver on application startup" as it hung
    qjackctl and jackd. If that happens, then you have
    to blow away: ~/.config/rncbc.org/QjackCtl.conf
    file and start all over with the proper settings.
    I could not locate the auto??? entry in this file.

2) Make SURE you get the correct qjackctl->Settings:Interface
    value for your audio hardware or you get: 'Cannot find PCM..."
    cryptic error.

I hope I got it all here.... (crossing fingers)

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