[Jack-Devel] Usage feasibility Q

[Christian Affolter]

Hi Robert,

On 30.01.2018 18:21, Robert Bielik wrote:
>> 2. recompile jack2 without dbus support
> 
> Ok, so I've compiled/installed jack2 without dbus support, and I'm now running jackd on a RT patched Raspbian Stretch (https://github.com/guysoft/RealtimePi)
> 
> And it seems to work wonderfully, no problem reaching buffer sizes below 1 ms. Happy joy!
> 
> I start jack with:
> 
> sudo jackd -P70 -d alsa -r 48000 -p 64 &
> sudo jack_wait --wait --timeout 10
> sudo jack_connect system:capture_1 system:playback_1
> sudo jack_connect system:capture_2 system:playback_2
> 
> I need sudo, otherwise allocation of shared memory + realtime prio setting fails.

Make sure, that the user which starts jackd is allowed to raise the real
time priority and memlock address space.

See http://jackaudio.org/faq/linux_rt_config.html

Most distributions ship and install a limits.conf snipped file with the
jack package. Here is an example from CentOS/Fedora:

cat /etc/security/limits.d/95-jack.conf

# Default limits for users of jack-audio-connection-kit

@jackuser - rtprio 70
@jackuser - memlock 4194304

In this case, the user has to be in the @jackuser group to be able to
raise the priority.



> And then I've setup the ALSA JACK PCM plugin, but to use aplay I need to use sudo aswell:
> 
> sudo aplay -D pcm.jack /usr/share/sounds/alsa/Front_Center.wav>
> Is there a way to set this up so sudo is not needed?

What error message do you get without sudo? Maybe your user has to be in
the "audio" group (or similar).

Regards,
Chris