Raspberry Pi 4 - USB not working under LinuxCNC

I installed the "linux-image-4.19.71-rt24-v7l+" image on my "Raspberry Pi 4 Model B Rev 1.5", Wifi and SSH enabled. I used Raspberry Pi Imager to burn the image (obtained from here, LinuxCNC.org site) onto a 64GB SD Card and to install the image on the Raspberry Pi.

Everything gets installed, but the USB ports don't work. Thus, no mouse and keyboard function. I checked the installation by using a Bluetooth mouse and keyboard and was able to operate all programs, incl. LinuxCNC.

My mouse and keyboard hardware is working, tested on a Windows machine. And no, my idea ist not to run a CNC controller via USB. I only want to use USB to use a mouse and keyboard.

Am I the only one with this problem ?
Any ideas how to enable USB?

Any help is appreciated.

Thanks

Stefan

This was a problem a couple of years ago, but I thought it was fixed...

I don't think that you need the kernel separately, the image file should include a kernel.

One suggestion would be to use the 64-bit image posted on this forum, rather than the 32-bit one from LinuxCNC.
forum.linuxcnc.org/9-installing-linuxcnc...aspberry-pi-4#237299

Hello Andy,

thanks for your quick reply.

I was aware of the post/link that you provided. I was a bit concerned downloading from that link not knowing the source (security reasons). I also didn't install a kernel separately. I just used the image file from linuxCNC.org:
linuxcnc.org/docs/stable/html/getting-st...lling_on_raspbian_10

Do you have a recommendation how I can proceed?

Thanks

Stefan

I created the image on the LinuxCNC website. So if you download that you are trusting me, and if you download the other one you are trusting elovalvo. From where I am sat I see little to choose between us

You do have the option of installing the preempt-rt kernel as a package direct from Debian, but would then need to compile LinuxCNC from source. This takes quite a long time but isn't particularly difficult.

I dont think the issue went away, I think the 3gb ram thing and elovalvos 64bit image were mediating the issue. I would suggest trying the ram thing, but I cannot find the doc entry for it.

If you revert the image to the non preempt-rt kernel in the config, and install a different preempt-rt, would you still need to compile linuxcnc?

cakeslob wrote:

ert the image to the non preempt-rt kernel in the config, and install a different preempt-rt, would you still need to compile linuxcnc?

I am not sure. I think that you would with a 64-bit kernel as the LinuxCNC packages are 32-bit. 

_But_ there are Arm64 packages on Debian now...

andypugh wrote:

_But_ there are Arm64 packages on Debian now...

But only for a week or so. I have not had time to test this on my Pi 4b but I think you should grab the Debian Bookworm image from here
raspi.debian.net/daily-images/
And install with the normal Raspberry installer

This will just give you a command line interface so run
sudo tasksel to install a windowing system of your choice

Then just type
sudo apt install  linuxcnc-uspace linuxcnc-uspace-dev
to install linuxcnc.

Please let us know how it goes
Note you will end up with V2.9

Hello guys,
first, I am super impressed with your quick and direct support, esp. since I recognize your names from a lot of other posts. That is great and I want to say thank you!

In the next days I will give your suggestions a try i.e., 3GB limit, kernel swap, different image, maybe recompile LinuxCNC - probably in that order. I will keep you/this forum posted about my results and hopefully a working solution.

I am very interested in getting a RasPi solution running, in combination with my Mesa 7I92H cards. I want to use such a low cost solution, still at high performance due to closed loop servo drives, ridgid tapping etc., for small formfactor CNC mills/lathes. Further motivation - I want to replace my annyoing NCCad/kosy CNC controller (from MaxComputer), at use with a Wabeco CNC mill. In another forum one member said, that this SW/HW platform has more bugs than features. In short, it is quite painful to use and yes, the bug level is pretty high.

Greetings

Stefan

Ok, I followed the "3GB limit" recommendation, as discussed here: forum.linuxcnc.org/9-installing-linuxcnc...i-4-8gb-2gb?start=20 . It worked! In my case, the Chromium web browser still works - in the link above it was reported to fail.

Approach: I modified the /boot/config.txt. First, I opened the LXTerminal window and entered "sudo nano /boot/config.txt" to edit the file. Then I added "total_mem=3072" under the "[pi4]" section. Then I rebooted.

To do that you need to terminal into your RasPi from another computer, since USB mouse and keyboard don't work.

Stefan

Hello Andy,

despite the 3GB memory limit workaround, I am very interested in a "how to" compile LinuxCNC from source. You mentioned it isn't particularly difficult and I would like to dive into this topic with the target RasPi in mind. Therefore, any help or pointers into this subject are apreciated, like a simple (less workload for the authour/writer) step by step approach, incl. pointers to where I can find "THE" LinuxCNC source files (GitHub?) and maby how to createt the build with corresponding "make" settings. All with RasPi 4B in mind.

PS: I am into programming embedded systems (ATMEL chips), and Windows systems, using C/C++, thus my interest. Now, I would like to get my feet wet in the Linux/Unix world.

Thanks
Stefan