RPI4 Raspbian 64 bit & LinuxCNC

I haven't had a chance to run Rods image yet, I did you through the build process and built an image.
You need to make sure that the config.txt file has the line that enables spi uncommented. Otherwise you wont have spi. But I can confirm that with the kernel from the build process spi is fine. (as I use the same one for my private image)

I've had some issues. The last ones I've built are not booting. I Was going to go back to basics

@rbobey, can you report what uname -v and uname -4 report?
I will try and upload the kernel as a deb file

@mkei 
As per Cornholio, just enable spi in the /boot/broadcom/config.txt I think thats the right location. Umm you break things if you try to overcloick it there too......

PS Cornelius upstream is not  Cornholio here. 

hi Rodw, right now I don't have my RPI4 at hand, but I checked "uname -a, uname -v", they indicate correctly the kernel version 6.1.46-rt13 but only SMP PREEMPT (not RT), good idea to check by loading only the kernel as a *.deb file, I'll try again tonight, sorry for Cornelius and Cornholio.

I also wanted to ask about the expected latency values in an RPI4B 4Gb for the steps indicated on the Linuxcnc website for kernel installation, I have tried with 6.1.x and 6.4.x and I get values of 100us to 200us, this using debian Bookworm, now using Raspberry OS 64bits documented in another thread on this forum improves incredibly, according to the linuxcnc documentation, 100us forward is not good for software steps, but up to 200us for remora or hostmot mmmmmmm, criteria and opinions are accepted

I'll look into this over the next few days. I tried to lock in some settings to avoid manual steps in the build process but maybe it did not work properly.

rpi-4-debian-bookworm-6.1.46-rt13-arm64-ext4-2023-09-03-1834-001.img :
 
Thanks for the good work so far also been following this thread !

I also tested rpi-4-debian-bookworm-6.1.46-rt13-arm64-ext4-2023-09-03-1633-001.img :

 
 

Just ran up rpi-4-debian-bookworm-6.1.46-rt13-arm64-ext4-2023-09-03-1834.img on a Pi4 2GB.

A couple of comments FWIW.

I'd make it automatically run the GUI as cnc on boot. I have a touch screen and had to go get a mouse and keyboard to log on (a touchscreen keyboard would be a nice addition as I'd guess a fair number of LinuxCNC users will be using such things).

It ignored wpa_supplicant.conf in the boot partition and it doesn't have raspi-config so getting the WiFi working involved connecting an Ethernet cable and mucking about with wpa_supplicant and dhclient.

It has come up on the Wifi but seems more 'klunky' than Buster.

Happy to test the next iteration.

Give this a whirl
drive.google.com/file/d/1Ve6LismgxL0OfYu.../view?usp=drive_link

Wifi is turned off only cos I've found it can affect latency, boots straight into gui. You can turn it back on by editing /boot/broadcom/config.txt as root, then just rebooting.

user:cnc
passwd:linuxcnc

I built it again last night but th epi complained about missing firmware on boot. It seems my board.txt file is corrupt
Here are some notes I posted on the developers email thismorning.
I've had some issues here last night but I think it's a corrupt environment at my end. I will reclone and build again tonight as it was working.
Follow the steps in instructions.txt in the linuxcnc branch
do a make purge-all before you start again
You may need to run  "make ncompile" after "make ccompile"

I would also suggest you edit  userdata.txt and set
MENUCONFIG="1"
CUSTOM_DEFCONFIG="0"

This will open the kernel menuconfig and prevent the use of  the custom defconfig (which may be corrupt)
When menuconfig opens, open general settings and look for preemption model. Set it to fully preemptible kernel
If that option is not there, go back one level and further down general settings, there is a menu option with "expert" in the name.  Set that to true and the fully preemptible kernel option will be displayed.
I have found this to be a very confusing recent change at kernel.org...

This is my next plan.

Cornholio: That seems better in terms of general responsiveness.

dtoverlay=disable-wifi was already commented out in config.txt so WiFi was enabled but it ignored wpa_supplicant.conf and I had to setup the WiFi from menu-config.

It didn't auto-login as cnc but setting autologin-user=cnc in the "[Seat:*]" section of the /etc/lightdm/lightdm.conf does the trick.

There's still no raspi-config installed or available in the repos but maybe that's a generic bookworm change.

There's no dhcpcd installed so setting a static IP for the ethernet port (used for talking to my 7i76E in my use case) involves more Linux hackery than a Google search for setting a static IP on a Pi would suggest. A simple old school edit of /etc/network/interfaces sorts it.

When the screen is woken from screensaver, it asks for the cnc users password.

On the Good News front, running up linuxcnc worked and I could jog my steppers (I'm testing on my Lathe project which is currently just a pile of electronics and wires on the bench).

Is this feedback useful? I'm assuming the aim is to produce a RPi bookworm image that works for most folk.