[Fluxus] Errors with start-audio and jack: memlock limits and real-time permissions

[Gabriel Wicki]

are you (the user executing fluxus) allowed to use jack with realtime-
priority on your machine?

g


On Wed, Oct 09, 2019 at 07:10:21AM +1100, Javier Candeira wrote:
> Hi again,
> 
> I was following the tutorial, and I got an error when first trying to read
> audio into Fluxus and using it for animation:
> 
> ```
> jcz at darthvader:~$ fluxus temp.scm
> Welcome to fluxus.
> Type (help) for info.
> Cannot lock down 82280346 byte memory area (Cannot allocate memory)
> Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
> JackClient::AcquireSelfRealTime error
> ```
> 
> The script I was running at the time:
> 
> ```
> (clear)
> (start-audio "system:capture_1" 1024 44100)
> (define (armonics)
>     (colour (vector (gh 0) (gh 1) (gh 2)))
>     (draw-cube))
> 
> (every-frame (armonics))
> ```
> 
> And the audio configuration seems right, I was just playing music videos on
> a browser and using jack to connect main PC output to input:
> 
> ```
> 21:26:56.676 JACK connection graph change.
> Cannot lock down 82280346 byte memory area (Cannot allocate memory)
> Tue Oct  8 21:26:56 2019: New client 'qjackctl' with PID 3552
> 21:27:09.139 Transport start.
> 21:27:32.764 JACK connection change.
> Tue Oct  8 21:27:32 2019: Connecting 'system:capture_1' to 'system:playback_1'
> 21:27:36.365 JACK connection change.
> Tue Oct  8 21:27:36 2019: Connecting 'system:capture_2' to 'system:playback_2'
> 21:28:29.283 JACK connection graph change.
> 21:28:29.339 JACK connection change.
> Tue Oct  8 21:28:29 2019: New client 'Fluxus' with PID 5324
> Tue Oct  8 21:28:29 2019: Connecting 'system:capture_1' to 'Fluxus:In0'
> ```
> 
> I'm running Jack through something called QjackCtl, which was what Ubuntu
> shows when you put "jack" into the Gnome Shell search box.
> 
> Cheers,
> Javier
>