Proposal RPi Linuxcnc Image Based on Raspi OS All welcome/encoraged to comment

bcm2712_defconfig.txt is the 16k-page one, it's broken by design, don't use it that's also pretty much the only difference between it and 2711, look at the diff between the two.
bcm2711_rt_defconfig.txt works on both Pi versions, I've tested it on my setup. it's the one that linux-image-6.12.x+rpt-rpi-v8-rt is built from. I only use SPI though (with my own drivers that mmap the registers), so I'm not sure how Mesa cards or GPIO would behave.

Ok you're telling me not to use a kernel that I have practical experience and have not had a single crash or anything similar. Neither have any users reported any crashes. I think an uptime of 39 days and being able to start Linuxcnc at anytime during that period with no crashes, latency errors or any other such issues proves to me that the kernel is solid and stable.
Before using it on the mill, I had been using to test some Mesa clones one based on a 7c81 and another more less based on the 7i92 design. I've also tested Ollie's riocore system, on the same 7c81 clone hardware early this year, before Oliie got his hands on a genuine Mesa 7c81 that he has made riocore formware for.
Could you point me to any papers, references or any such peer reviewed articles explaining why the 16k page kernel is broken by design.

So this time I will stand by my choices for the RPi5. Unless of course you can provide hard evidence as requested above.

Even this page says to config 2711 for RPi4 to RPi3 and 2712 for RPi5.
www.raspberrypi.com/documentation/computers/linux_kernel.html

unknown wrote:

Could you point me to any papers, references or any such peer reviewed articles explaining why the 16k page kernel is broken by design.

yeah no, sorry, I have used too strong wording there - 16k pages used to cause compatibility issues with older software, but I believe that has been a non-issue for several years now.

unknown wrote:

Ok you're telling me not to use a kernel that I have practical experience and have not had a single crash or anything similar.

not really, because I - still - have not seen the exact kernel configs that you've used in your images. are they on github somewhere?

all I'm saying is that the ONLY difference between bcm2711 and bcm2712 configs is that the latter enables 16k pages. we don't need them, the performance increase is practically zero for our application - LinuxCNC does not allocate huge amounts of memory in runtime. 4k pages work just fine and have been used since forever, bcm2711 config works perfectly on Pi 5, I've been making chips with it for a few months now without issues.

I don't get it - if you have a working vendor-provided RT kernel that you can just apt install, why bother building your own with a useless feature that no one needs?

Config attached.

One of my previous posts as a zip archive of the rpi-image builder used to build the RPi5 & RPi4 images.

I'm of the opinion of keeping the kernel locked is not such a bad idea. It prevents users from messing things up.
It can also save "I've updated my kernel and I have xxyyzz issues" and sometimes trying to help some people out is like pulling teeth. Sometimes you have to ask for the same information a couple of times because for whatever reason they don't think it's relevant. And sometimes Linuxcnc is a users first venture in Linux, after maybe using Mach or grbl. There's no reason why an experienced user can't use alternative kernels if required or wanted.
And TBH I don't think kernel building is such a large task. The first one I built was around the time of Redhat 6.0 on a 486 with 32MB RAM (Maybe around '99 or something like that). Yes it was a very, very slow task. Back in the day were one had to hand edit files to get a dial up connection.

As for updates.....there's some user's that have machines running on Ubuntu based versions of emc2. Bit like the ecu of a car\truck\snow mobile\jetski\road bike\off road bike or similar, not often an owner will think of updates if any are available.

I see where you're coming from. I very much don't agree with it, but that's just me.

I compiled my first kernel for RedHat 7 in 2001 I think. had no idea what I'm doing but since then, the novelty of compiling kernels - or anything, really - has worn down, mildly speaking. I'm a software engineer by trade, very lazy at that, and I prefer to a) update things as soon as possible, because the more versions I skip, the harder the update would be, and b) don't do work if I can avoid it - don't write code if I can use a library, don't compile my own kernel if a pre-built one is available, don't configure things that I don't need configured, etc., because if I do that, it means I now own that thing, and if there is an issue with it, it is my responsibility if not to fix it, then to at least investigate if the issue was caused by my changes.

I guess we have differing world views, and that's perfectly alright!