RockPro64

In theory you can resolve the conflicts manually, but it is a lot of work especially in code that you don't necessarily understand.

Is there anything useful in this thread?
forum.armbian.com/topic/7301-booting-a-r...mments#comment-55457

(I just did a google search)

I saw this previously but I did not post it because I wasn't 100% sure that this is what it looks like it is. Rockchip has an "rt" development branch. I can't tell if this is a real-time patched kernel, preempt or otherwise.

Pine generally seems to use Ayufun kernels so the Rockchip kernel is likely missing some board specific changes.
github.com/rockchip-linux/kernel/tree/develop-4.4-rt176

This repo has realtime 4.4.167 kernel for 3399 soc
github.com/rockchip-linux/kernel/tree/develop-4.4-rt
i have not tested yet but seems ok.

Did you have any luck with these boards?

No.
rt kernel with default .config does not work .

What kernel did you use? One from the rockchip repo? Did everything on the rock pro work right with this kernel?

Getting linuxcnc to work with it shouldn’t be that big of a deal, it’s getting an RT kernel to work on the board if the board manufacturer didn’t supply it that can be a problem.

stock kernel 5.2 for rockpro64 has been released
git.kernel.org/pub/scm/linux/kernel/git/...x-rockchip.git/refs/
also real time patches
cdn.kernel.org/pub/linux/kernel/projects/rt/5.2/

I built the linux-stable-rt-4.19.31-rt18 kernel and installed it.
I downloaded the cyclictest suite and ran it several times. The average latency is 3 microseconds. Running it via ssh the max was 45 or 48 until I logged from a wireless keyboard and the HDMI video. I started X and LXQT during that startup, the max went to 58.

I just started it again with the -h option to produce a histogram, now the max is 62 and the average is 4.

Alan

What distro did you use for your build? Those are some great looking latency tests. I'm looking to put a Mesa PCIE card into the Rockpro64 slot and make it a full-fledged controller, so this is very promising.

with the fpga card or a eth you do not need latency at all
it is internal hardware steps that are generated
no software timing involved