Raspberry Pi 4

[quote="Gene1934" post=140249
I realize I may be tarred and feathered for the suggestion, but isn't this as good a time as any to switch to working in python-3.7[/quote]

It would be a very good idea, but do we really want to re-factor all the Python in LinuxCNC with the 2.8 release imminent? That just seems to be asking for trouble.

As far as I know the lathe macros are the only thing not currently working in Buster. Though I do need to do some more testing. And the lathe macros are not a released part of LinuxCNC.

andypugh wrote: [quote="Gene1934" post=140249
I realize I may be tarred and feathered for the suggestion, but isn't this as good a time as any to switch to working in python-3.7

It would be a very good idea, but do we really want to re-factor all the Python in LinuxCNC with the 2.8 release imminent? That just seems to be asking for trouble.

I wasn't aware that 2.8 was about to be set. You are of course correct, and if 3.0 is on the horizon, that obviously would be the time.

As far as I know the lathe macros are the only thing not currently working in Buster. Though I do need to do some more testing. And the lathe macros are not a released part of LinuxCNC.[/quote]

Buster had a surprise. I had done a RealtimePi conversion based on buster rc1. Realtime was very good, but then a day or so after the release announce, came a good sized update including the video libs. Took full screen glxgears from about 1.7 fps to 19 fps or above, but that also removed the rt-preempt kernel, so latency went in the crapper. I have linuxcnc built, it installs on that buster, but have not found the tool to build a u-boot style deb of that rt kernel.

The pi will not build lcnc without external swap, the OOM kills the build in the middle of the RS-274-d interpreter. Stok it has a 100 meg swapfile, but I've mounted a 10GB swap on an 120GB ssd, so now it slogs on thru, taking about 4 hours for a -j1 build. Higher J numbers don't help much due to the usb2 sized pin-hole to the swap, but it just keeps on till its done. I did that on stretch, and it installs on buster but needs an apt --fix-broken -i to fix it. If and when I get an rt kernel built, I'll rebuild it on buster and see what needs fixed if anything.

After finding the price of a 7i80 to be a big buck and a half, + $65 for a 2 gb rp4, that will bring the total I've spent on miniature computers and interfacing to nearly $700 since I started this, so I think even if I can't build and install an rt-preempt kernel for buster, that I continue to run a stretch that runs the machine well even if the video is way behind the machine. But I'll also keep looking for a deb builder that will build a u-boot kernel style deb. If you know the name of such a tool, I'd appreciate it.

That $700 exceeds the cost of the motors and screws to convert this door blocking piece of iron to CNC as I made nearly everything else. So I'm going to let the software catch up for a couple months. In the meantime, everything is still running master.

Thanks Andy.

Gene1934 wrote: Buster had a surprise. I had done a RealtimePi conversion based on buster rc1. Realtime was very good, but then a day or so after the release announce, came a good sized update including the video libs. Took full screen glxgears from about 1.7 fps to 19 fps or above, but that also removed the rt-preempt kernel, so latency went in the crapper.

There was an update to the 4.19-y-rt Raspbian today but the RealtimePi guy is away from home until the end of this week. So I imagine realtimepi will be working again some time after that point.

Gene1934 wrote: Buster had a surprise. I had done a RealtimePi conversion based on buster rc1. Realtime was very good, but then a day or so after the release announce, came a good sized update including the video libs. Took full screen glxgears from about 1.7 fps to 19 fps or above, but that also removed the rt-preempt kernel, so latency went in the crapper.

There was an update to the 4.19-y-rt Raspbian today but the RealtimePi guy is away from home until the end of this week. So I imagine realtimepi will be working again some time after that point.

I'll check into git and check the timestamps.

Thanks Andy.

Cheers, Gene Heskett

There was an update. I have tested it, works fine. Go for the rpi-4.19.y-rt version.

As far as I understand it there are a few, specific python libraries that are not included in buster anymore. They are the problem, not python 2.7 really. marc.info/?l=debian-devel&m=146974136510682&w=2

Gene, I read your journey. I invested in the BeagleBone Black approach years ago, made own caps and what now. In the end the platform couldn't deliver. Too slow graphics, too limited memory. Unusable. But the RPi4 is another thing. Here it actually works. I have compiled both the kernel and linuxcnc on the RPi4 with 4 GB memory with just 100 kB swap that came with it.I can run the lathe in the same way as the Intel PC (except lathemacros then). I definitely see the RPi4 as a possible platform.