LinuxCNC on Raspberry Pi 5

Cornholio, I have just followed the commits on the raspberry pi kernel git
github.com/raspberrypi/linux/commits/rpi-6.1.y
It is desirable to match the mainline kernel with the preempt-rt kernel
6.1.67 was committed on 11 Dec but it has not been merged into 6.1.y
The next merge ocurred after committing 6.1.68 so there is not a clean match with the 6.1.67 RT patch.
Previoulsy there was 1 for 1 mapping with the kernel versions. The sudden flurry I assume is due to the Pi 5.
The production 6.1.63 kernel would need to use the 6.1.47 patch so quite a gap.

Probably the best commit to clone from would be e41b05a8fc73f95425aceaf15a68fc25da1d1fe5 where 6.1.68 was merged in as that should include the 6.1.67 changes and only be one version away from preempt_rt

When you use kernel source from kernel.org there are ways to match the versions eactly.

None of those are “bleeding edge” if you look at the progression of the mainline kernel, which is well past the 6.1 series.
Quite honestly, after going through the process, as it stands the most usable route for the RPi 5 is a Raspberry OS image with a real time kernel of the appropriate version and Linuxcnc either installed via self built packages, which doesn’t take that long. The other secret is to change from Wayland to X as the compatibility layer is not optimum for UIs that have calls to X libs. This is a must if a user has a preference for a xfce desktop.
Another thing to keep in mind is eventually sysfs will be dropped from RPi kernels as it a depreciated feature. This will mean some changes to user land access to GPIO, not that it will affect Linuxcnc, but it would be something worth tracking. This info comes from the RPi forum, mainly from when questions arise from access regarding The RPi 5, which seems to be a little messy and unclear to a great many users. Libgiod seems to be the recommended way. Whilst it’s neither here nor there, some of these developments would be worth tracking.

On another note, keep safe and I hope that the fire nor floods affect you mate, seems like the last thing you need on your plate.

My interest is being able to build a img that has Linuxcnc preinstalled on the 6.1.x kernel to remain compatibility with Debian 12 to complement the other installers I have built. Eventually, the kernels and patches will align so until then early adopters will have to follow your methods

edited

 

Please use Balena Etcher to install the image in this thread rpi-imager does not work
forum.linuxcnc.org/9-installing-linuxcnc...pberry-pi-4-5-images
i think we are good with the Pi 5 now except for sound. If anybody knows their way around kernel settings for sound, please let us know


 

Would it be possible to provide an image for the functional Rasberry Pi 5 configured to access the GPIO?

rufino wrote:

Would it be possible to provide an image for the functional Rasberry Pi 5 configured to access the GPIO?

Does the existing driver work? linuxcnc.org/docs/stable/html/drivers/hal_gpio.html

If not it will be up to the developers to implement something. Not something I do.

libgpiod May work on the RPi5, as of now the only known working interface for linuxcnc is Ethernet.
All I can suggest is to try the above mentioned driver and report back. Or bang your head against a wall wishing you bought a RPi 4, hahaha, cos that’s where I am.
Whilst it’s been touted as the greatest thing since sliced bread at the moment it’s just a pile of flour, yeast, a pinch of salt and a jug of water without a recipe.
To be fair I doubt Linuxcnc was on the foundation’s radar, but it is frustrating. It has potential but not quite yet.

rufino wrote:

Would it be possible to provide an image for the functional Rasberry Pi 5 configured to access the GPIO?

The image you can download from this links
forum.linuxcnc.org/9-installing-linuxcnc...pi-5?start=20#285747
forum.linuxcnc.org/9-installing-linuxcnc...pi-5?start=60#287616


It works fine with the hal_gpio module as reported here

forum.linuxcnc.org/9-installing-linuxcnc...-pi-5?start=0#285243

This image does not appear to have any problems with either Ethernet or video drivers

It does not seem elovalvo made any changes to the hal gpiod driver acode. He just configured th eports appropriately, Therefore, the official image on the downloads page  should also support it