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#1 2023-08-29 22:01:23

torquebar
Member
Registered: 2021-09-15
Posts: 54  

Chimaera sound/music issues

I'm using chimaera (IV) and update it regularly, have not many problems with it so I don't see why I would upgrade; anyway, isn't Devuan a rolling release?

The current problem I *do* have is with sound or rather music apps; namely, jack_capture and qjackctl. The context is the group of apps I use to create my own backing tracks for guitar, not all each time but usually started in this order: qjackctl, qsynth, Yoshimi, Hydrogen, Rosegarden.

jack_capture is driving me nuts (and not only when using Devuan), here's the error message that no one seems to know how to put out of its freakin' misery:

Cannot lock down 107341338 byte memory area (Cannot allocate memory)
>>> Warning. Could not set higher priority for a SCHED_OTHER process using setpriority().
Cannot use real-time scheduling (RR/5) (1: Operation not permitted)
JackClient::AcquireSelfRealTime error
>>> Recording to "jack_capture_02.wav". Press <Return> or <Ctrl-C> to stop.
>>> Please wait while writing all data to disk. (shouldn't take long) 
   |"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""|
00:|                                                                 |
01:|                                                                 |
Buffer: 4.03s./4.03s    Time: 0.07m.   DHP: [ ]  Overruns: 0  Xruns: 0

The other one is qjackctl which doesn't recognize an already started
Yoshimi synthesizer which thus doesn't show in the qjackctl 'connections'
dialog. Yoshimi in this case is the rather outdated v-1.7.4 but I have
no idea if this is a factor.

Any help would be appreciated, particulartly with jack_capture.

--
Tuesdays are Devuan days: GNU/Linux 4 (chimaera), BIOS-boot, DM=Unknown,
Kernel=5.10.0-25-amd64 on x86_64, DM=Unknown, DE=XFCE, ST=x11,grub2, GPT,
https://imgur.com/x2A9zHw.png      https://i.imgur.com/RsbswMP.png


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#2 2023-08-29 22:15:40

golinux
Administrator
Registered: 2016-11-25
Posts: 3,233  

Re: Chimaera sound/music issues

torquebar wrote:

. . . anyway, isn't Devuan a rolling release?

No! At least as to what I understand a rolling release to be. It is a "stable" release. "testing"is a rolling release until it becomes the next "stable" release. See:

https://www.devuan.org/os/releases

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#3 2023-08-29 22:28:13

torquebar
Member
Registered: 2021-09-15
Posts: 54  

Re: Chimaera sound/music issues

golinux wrote:
torquebar wrote:

. . . anyway, isn't Devuan a rolling release?

No! At least as to what I understand a rolling release to be. It is a "stable" release. "testing"is a rolling release until it becomes the next "stable" release. See:

https://www.devuan.org/os/releases

:-)

That HAS to be the fastest response I have ever received in any forum, group or mailing list!


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#4 2023-08-30 07:39:41

GlennW
Member
From: Brisbane, Australia
Registered: 2019-07-18
Posts: 613  

Re: Chimaera sound/music issues

Hi, I think jack wants realtime access from the kernel.

uname -a will show your current kernel version, yours should have rt in it's name.

(edit) terrible typos

Last edited by GlennW (2023-08-30 07:40:16)


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#5 2023-08-30 11:39:34

torquebar
Member
Registered: 2021-09-15
Posts: 54  

Re: Chimaera sound/music issues

GlennW wrote:

Hi, I think jack wants realtime access from the kernel.

uname -a will show your current kernel version, yours should have rt in it's name.

(edit) terrible typos

Thanks, I'm on slackware right now:

# uname -a
Linux darkstar.example.net 5.15.117 #1 SMP PREEMPT Thu Jun 22 15:39:49 CDT 2023 x86_64 AMD FX(tm)-8150 Eight-Core Processor AuthenticAMD GNU/Linux

...similar problems with jack_capture on several distros. Jack itself seems to work OK, but my technical polish is the equivalent of about grit-20 sandpaper. I thought jack was needed TO provide virtual low latency so why use it if one has a real low-latency kernel?


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#6 2023-08-30 12:04:52

delgado
Member
Registered: 2022-07-14
Posts: 184  

Re: Chimaera sound/music issues

torquebar wrote:

I thought jack was needed TO provide virtual low latency so why use it if one has a real low-latency kernel?

jack needs a real-time-kernel to be able to schedule the audio-related processes accordingly.

The error message (#1) could also mean "your user is not allowed to do real time scheduling", even if the kernel is capable.

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#7 2023-08-30 17:14:47

torquebar
Member
Registered: 2021-09-15
Posts: 54  

Re: Chimaera sound/music issues

delgado wrote:
torquebar wrote:

I thought jack was needed TO provide virtual low latency so why use it if one has a real low-latency kernel?

jack needs a real-time-kernel to be able to schedule the audio-related processes accordingly.

The error message (#1) could also mean "your user is not allowed to do real time scheduling", even if the kernel is capable.

I'm on Suse-Leap right now but you just solved my problem, or at least provided a workaround.

This distro does run a RT kernel (I think)

# uname -a
Linux localhost.localdomain 5.14.21-150500.55.19-default #1 SMP PREEMPT_DYNAMIC Tue Aug 8 22:15:01 UTC 2023 (9908c29) x86_64 x86_64 x86_64 GNU/Linux

When I read 'permissions' I decided to try it as root, it didn't work either

But then I logged back as userr, retried ...and BINGO.

Beats the rcap out me lieutenant, but nice work  :-)


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#8 2023-08-30 18:00:10

rolfie
Member
Registered: 2017-11-25
Posts: 1,114  

Re: Chimaera sound/music issues

torquebar wrote:

This distro does run a RT kernel (I think)

# uname -a
Linux localhost.localdomain 5.14.21-150500.55.19-default #1 SMP PREEMPT_DYNAMIC Tue Aug 8 22:15:01 UTC 2023 (9908c29) x86_64 x86_64 x86_64 GNU/Linux

No, that not a RT kernel, that would look like this:

Linux localhost.localdomain 5.14.21-150500.55.19-default #1 SMP PREEMPT_DYNAMIC RT Tue Aug 8 22:15:01 UTC 2023 (9908c29) x86_64 x86_64 x86_64 GNU/Linux

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#9 2023-08-30 19:33:47

torquebar
Member
Registered: 2021-09-15
Posts: 54  

Re: Chimaera sound/music issues

thanks


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#10 2023-08-30 22:33:07

GlennW
Member
From: Brisbane, Australia
Registered: 2019-07-18
Posts: 613  

Re: Chimaera sound/music issues

For what it's worth, Pre-empt is not RealTime, but close.

I hope it keeps working for you.

See how you go when playing back 14 tracks while recording overdubs in real time.

Minimal xruns.


pic from 1993, new guitar day.

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