Installing LinuxCNC 2.9 on Raspberry Pi 4B with Preempt-RT kernel

To anyone looking for a low latency board computer that you can actually get your hands on, check out this thread.

forum.linuxcnc.org/18-computer/48113-odr...ent-for-raspberry-pi

We've managed to get sub-20 microsecond latency under realistic test conditions.

> It is looking for Docker, although i wonder why

It uses docker as a stable build environment. That controls a lot of variables for you.

alangibson wrote:

To anyone looking for a low latency board computer that you can actually get your hands on, check out this thread.

forum.linuxcnc.org/18-computer/48113-odr...ent-for-raspberry-pi

We've managed to get sub-20 microsecond latency under realistic test conditions.

We are hoping to migrate this to the Armbian build system which I've been playing with for a while. I've missed something with the preempt_rt but with Alan's help, I think it will be pretty easy to sort out from here. That will reduce it to a one line build command.

Hi Alan,

I have been running through the instructions all is going well (after setting up docker) but when I run

debuild -uc -us

after some time compiling taskmodule.cc I get the error below , do you know what this error means and how to fix it.

I should add that I killed the process as it seemed to have crashed.  


Thanks
Nick


Compiling emc/task/taskmodule.cc
g++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [Makefile:287: objects/emc/task/taskmodule.o] Error 1
make[2]: Leaving directory '/home/nick/build/src'
make[1]: *** [debian/rules:50: override_dh_auto_build-arch] Error 2
make[1]: Leaving directory '/home/nick/build'
make: *** [debian/rules:38: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2
debuild: fatal error at line 1182:
dpkg-buildpackage -us -uc -ui failed

Still couldn't get debuild to complete so reverted to using build in place. this time it compiled.


Regards
Nick

Thanks for this guide.  I think I got everything installed properly but encountered a couple areas where I had questions:

1. QT Designer script asked for "Run In Place" vs "Package" installation; I assumed Package.
2. sudo dpkg -i mesact_1.1.2_arm64.deb had an error message saying it wasn't a valid Debian archive; I downloaded mesact_1.2.3_arm64.deb and installed instead.  Not sure if this will be an issue with the previous compilation steps before it.

Thanks again!

~Mor