docs: help to resolve error sched_setscheduler Operation not permitted

[drackp2m]

Signed-off-by: Marc Jovaní González [email protected]

[drackp2m]

Status before applying the correction:

Logs before applying the correction (sudo journalctl -u klipper-mcu.service):

Apply solution, restart service and check status:

Logs after applying the solution:

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I have been a Klipper user for quite a few years, always using a RaspberryPi 3B+, currently I set myself the challenge of moving all my setup to OrangePi Zero 2W, and trying with different distributions, many of them gave me this error. And it had me pretty crazy until I found that solution.

I would have been very grateful to have this tip in the documentation.

[JamesH1978]

Thanks for the PR, yes details are also pinned in the discord, as we usually see it on BTT's CB series on armbian. We don't really want to link to forum posts due to their nature of maybe not always being there. We also wouldn't want to lay blame on anyone either in documentation, it isn't the place for that, so the comment about systemd devs should probably be removed.

Just a description of the possible problem and a solution would be best for official documentation.

Thanks
James

[drackp2m]

Ready. I hope this version aligns more with the project guides.

I thought that referring to the forum would be a good idea to minimize changes in the documentation, but I did not take into account that it could lead to the problems you mentioned.

If you consider any other change necessary, I will be happy to do my best to improve my contribution.