USB not working on 64 bit ubuntu core on raspberry pi

device
1

Hi, I am trying to run 64 bit Ubuntu Core on a Raspberry Pi compute module 4. USB does not seem to work either on an existing installation - I don’t get USB access to a cellular modem - or on a new installation - USB keyboards don’t work. Neither Core 20 nor Core 22 work, but the 32 bit versions are fine.
This would seem to be a regression, since I have previously installed Core 22 on a compute module 4.

Regards, Andrew

2

well, USB is provided through your base board, i’m running two CM4’s over here with UC18 and UC20 on a standard RPi baseboard as well as on a waveshare one… what base board do you use, are all the base board specific bits (devicetree overlays etc) added to your config.txt ?

3

I am using a waveshare Industrial IoT Wireless Expansion Module, but I have also tested this on a standard RPi baseboard. I have not added any customisations to the base config, so I could be missing something. However, USB functionality seems to be standardly enabled in Ubuntu Core, and works fine on the 32 bit versions.

I would like to play around with boot configurations, but I have not been able to find any information about how to change the config.txt on Ubuntu Core. Config.txt is found inside the pi snap, and I don’t believe it can be directly modified. Also the Ubuntu Core pi snap seems to be different in this respect to the standard Ubuntu pi snap.

4

Just verify that your config file inside /boot/uboot/config.txt have the following assignment under the CM4 section (if any)

Or just plop the line on top of the config.txt file: dtoverlay=dwc2,dr_mode=host

5

just plug the SD in a PC and edit it on the first partition …

at runtime it is mounted under /run/mnt/ubuntu-seed/ in UC20 and 22 in case you want to edit on the device directly

6

This worked. I don’t know why I didn’t work it out for myself, but thank you for your help.

This is already in the config.txt file. What I needed was otg_mode=1

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