Rod,
Thanks, your instructions have helped me a lot, Also your Youtube video on installing from source. Thought I would add some further thoughts on this topic that might be of general interest.
I'm in the process of building a second CNC machine using LinucxCNC. This is also a Taig, but this time a lathe. The current PC I use for the mill is getting long in the tooth so I thought it was a good chance to try one of those small cheap mini PCs, given the current cost of R-Pis. The PC is a Kamrui AK1 using an N5105 processor from Amazon. It's got better specs than the well-known GK1 mini, but the N5105 CPU puts it in the category of "problematic hardware"
I was impressed with the way it handles Windows 11, seems quite responsive for such a low end CPU. I wanted to check the latency before going much further, so I booted the LinuxCNC 2.8.4 live USB. However, it stalled with some repeating messages about SDHCI hardware, whatever that is. Next I tried the bullseye live CD. This booted and installed (to an add-on 500GB 2.5" HDD) just fine, but no WiFi and only 800x600 graphics. The Intel graphics HW in the mini PC seem to need a bookworm 6.x kernel, which I got and installed as Rod described, no problem. The WiFi HW is the Realtek RTL8821CE, and no Debian package supports it, so I built it from github source (
github.com/lwfinger/rtw88
). Again, straightforward once you find it. The ethernet HW/FW worked out of the box, but I haven't tried it with a Mesa card yet.
For the LinuxCNC, apt did not work. synaptic listed the 2.9 packages but would not install them (held broken packages). I tried to set up repositories and keys, but it was very confusing: which repositories, which distro? How do you get the key, now apt-key does not work? Perhaps someone can describe a way to set up the repositories.
So I ended up building LinuxCNC from source, as described in Rod's video. I like the CNC menu rather than CLI, so I built a deb and installed that - all straightforward so far. Earlier I'd built "run-in-place" which also worked fine.
As a matter of interest, the latency jitter looks pretty good, being of the order of 50000 - 60000. My older PC using an FX8570 CPU works very well and comes in just under 100000, so the mini should work at least as well. By the way, if you inadvertently choose the wrong kernel in grub and test the latency, you will be horrified: 8,000,000 nS jitter. Stupid mistake, but now I know what the realtime kernel does.
So it looks like these mini PCs are viable, but need a bit of setting up.
