Custom Mint-19.2 with Linuxcnc

Interesting.
Would it be possible for you to download a std Mint 19.2 XFCE iso and try booting from that ?

Another thing to try is booting with by changing your UEFI to legacy or compatibility mode to see if that helps.
I have seen that behaviour before but only on an early intel iMac. But that has a 32 bit UEFI and needs the image modifying to boot a 64 bit kernel. I never looked that far into it.

I downloaded Mint 19.2 XFCE and was able to boot from USB flash. My normal OS on this system is Ubuntu 18.04 server which should be very similar to Mint 19.

A quick look at the ASRock forum revealed many people having trouble booting Linux flavors from USB. There was no pattern evident from the posts I read. Apparently there is no Legacy boot mode. It seems Intel removed that capability from the Gemini Lake series of CPUs.

I'm willing to try something else if you have any ideas. Meanwhile I'm going to try cutting something with my router using your RTAI version.

John

Ok Intel seems to have decreed the removal of Legacy boot from Gemini Lake Platforms.
I just tried booting my T530 Thinkpad with that image, I usually use VBox to check images, and have the T530 set to boot in legacy mode. I had the same issues. I think it may be a kernel issue related to video in UEFI mode. Or maybe a grub thing, as I had an issue previously......it's mentioned somewhere earlier in the thread, and delayed the release of a RTAI iso. So the boot issue is confirmed, sorry about the issue and for not thoroughly checking and also thanks for the feed back and bringing it up.
I'm going to boot a RT_PREEMPT image and report back. In the meantime when you get the grub screen press e to edit the entry and add nomodeset to the kernel command line and if quiet & splash are there remove them. I'm not sure if this will work but lets rule it out anyway.

UPDATE:
Ok booted a RT_PREEMPT version with the T530 set to UEFI only mode, and am typing this from a Live Session. There is a new RTAI kernel mentioned on the forum. I'll have a look at the config and see if intel GPU driers are enabled in the kernel (which I'm thinking maybe the issue). Towards the end of the day I'll experiment and see what I can come up with.
But for the time being, my Beagle, known as The Butter Dog, needs time at the park.....and the Beagle must be obeyed.

OK T530 set to UEFI only boot
Rebuilt RTAI 4.14.173 with Intel GPU drivers
Booted to desktop fine and now typing this from a live session.
Need to rebuild rtai modules & rebuild linuxcnc to suit the new kernel.
Once I'm happy with all that I'll throw up an ISO on da goolge drive.
So far so good.
The Big Question is what latency numbers will we get.

Nomodeset did not help. I have to admit adding that parameter at boot is testing my Linux knowledge a bit. I vaguely remember having to do that in the distant past but it looked very different then!

Our Beagles Brewster and Blush say Hi to The Butter Dog. They're taking a break from chasing squirrels out of our yard.

OK booting is successful via UEFI now, at least on my Test machine.
Issues have arisen forum.linuxcnc.org/9-installing-linuxcnc...ges?start=140#161047

Hopefully it's some dumb mistake on my part or particular to my machine and easily fixed.

Butters replies AAAARRRRRROOOOOOOOOOOOOOOOOOO!!!

Bad news mate, whilst I managed to produce a RTAI UEFI bootable image only one core is initialised when booting UEFI. Legacy booting, which is no good for you and your board, will initialise all cores.
So this is where we are now.......tho it does appear strange.

RTAI is best on 2 cores. One for real time and the other for everything else.

RTAI is not meant to run with EFI. You are going to have lower latency with legacy BIOS.

Intel replaced the mess that was BIOS with an even worse horrendous OS called EFI. Now we have to work with the garbage they force upon us. Intel has had a better option for 20 years. They could have used coreboot/LinuxBIOS. But our PC's have to be secure from us so we have EFI.

I'm not expecting to be able to interact with the UEFI once booted into the OS, just really curious why only one core of a dual core system is started. It's as if it's a single core CPU. Whilst a non patched or RT_PREEMPT kernel are fine, both cores are initialised and available. Running cat /proc/cpuinfo even shows the difference.