Hello folks,

I have been struggling for the last several days trying to get any version of Puredata to work correctly on Chromebook Crostini. It almost works. It runs and I get sound but it is extremely scratchy and broken up.

Firstly, I know that audio can work because csound 6.12 works well with perfect sound. No hiccups at all.

I am running 83.xxxxx.77 official version of chromeos on an acer 14" Chromebook. I have tried many things to try to get some version of Puredata to work. I have used apt-get to install pd-version 0.49.x. I have downloaded and built from source pd versions 0.50.2 and 0.51 (brand-new). Every version runs and makes a similar complaint both on the command line and in the running program (see below):

"priority X scheduling failed; running at normal priority" - where X is 94, 92, 8 or 6.

I have tried multiple command line switches and setup parameters all with the same results. Additionally, as you can see from the screencapture below, once DSP is turned on the helpful 'Audio I/O error' message is displayed. I have researched and tried many things including adding the audio group and my name to '/etc/security/limits.conf' with the same result. Also, I have run pd without realtime scheduling: 'pd -nrt' with the same scratchy sound results.
I would be extremely grateful to anyone who could help me solve this problem or point me in the right direction. Perhaps I am missing something simple and/or obvious. Thank you in Advance!

@pman Scratchy results suggests the audio buffer is too small. Try setting the "Delay (mSecs)" to 80...... which is usually enough.

But there has been a specific thread on the Pd list....... https://lists.puredata.info/pipermail/pd-list/2015-04/109949.html
It seems very likely that thread will solve your problem.
It suggested running the realtimeconfigquickscan and then applying the results.......
https://wiki.linuxaudio.org/wiki/system_configuration

I have seen Pd not accept new settings though when it gets "stuck" with impossible settings.
If still no luck then open this file.... fix.pd which will force a reset of Pd audio settings...... although I doubt that will help for your problem as it stands.
David.

Thank you for your help David. I tried setting delay to 80 and 100 with no luck.
I did run 'realtimeconfigquickscan.pl and am attaching the results. I'm also attaching a copy of my '/etc/security/limits.conf' file. It is worrysome that I cannot set a realtime priority even though I have that parameter set in limits.conf.
Thanks again for your help!

limits.conf:

output from realtimeconfigquickscan:

@pman I am not a Linux user, but "chrt operation not permitted" probably means that your settings above are being ignored........ https://unix.stackexchange.com/questions/114643/chrt-failed-to-set-pid-xxxs-policy-on-one-machine-but-not-others has a solution.
Then hpet will be necessary I think for jack and alsa and maybe need to be configured in their settings once it is enabled.
https://linuxmusicians.com/viewtopic.php?t=2296
You probably should reduce swappiness to 10 to improve performance as the analysis suggests.
Strange that rtc is not found. Might not be necessary with hpet but probably easily fixed.
If that does you no good because the Kernel problem persists then you will need help in the audio threads in forums for your os.
David.