Ubuntu server 19.10 rpi4 adafruit python library cannot open /proc/device-tree/compatible

I am having all sorts of problems trying to build a snap.

I’m trying to install my snap on an ubuntu server 19.10 running on RPi4 because I ran into issues supporting ALSA in the Raspian OS. I’m now getting different permission errors when running in a different OS.

The application uses several third party libraries. One such library is NeoPixel from Adafruit. The python library is getting an access denied error when trying to open /proc/device-tree/compatible. They also try to open the /proc/device-tree/model and gpio pins.

Is there some sort of document that explains which plug/slot provides which access?

How do I install the pi widget that provides the GPIO pins?

I can’t find any documentation describing how to install one. I tried snap install pi with no success.

the hardware-observe interface should provide you read access to /proc/device-tree.

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Is there a pi gadget for rpi4? I tried installing the channel for rpi3 but get an error about the model not matching.

what exactly do you mean by this ? a gadget ? i fear there is none in the store yet …

you could try out my core18 pi4 developer image though …

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Pardon the interruption. I thought that the snap core for RPi4 was on hold?
Been using the 19.10.01 server pre-installed image on RPi4 4GB without issues since GA in Nov’19.

Kind regards.

Ubuntu Core for pi4 is planned for core 20, meanwhile the kernel might get backported to an 18.04 point release which will make an 18.04 server image possible, i dont know what the plans are to have a core18 based pi4 image though, since we can not just replace the kernel with a newer version on existing installs without breaking them (making them unbootable after upgrade) it would have to be a dedicated pi4 image with a dedicated kernel snap just for the pi4. perhaps @sil2100 can elaborate what the exact plan is, since he is doing most/all images nowadays …