Raspberry Pi 2 missing GPIO slot

kyrofa 2017-11-29 00:20:00 UTC #1

Using the official rpi Ubuntu Core image, these are the interfaces I see:

$ snap interfaces
Slot                      Plug
:account-control          -
:alsa                     -
:autopilot-introspection  -
:bluetooth-control        -
:broadcom-asic-control    -
:browser-support          -
:camera                   -
:classic-support          classic
:core-support             core:core-support-plug
:dcdbas-control           -
:docker-support           -
:firewall-control         -
:framebuffer              -
:fuse-support             -
:greengrass-support       -
:hardware-observe         -
:hardware-random-control  -
:hardware-random-observe  -
:home                     -
:io-ports-control         -
:joystick                 -
:kernel-module-control    -
:kubernetes-support       -
:kvm                      -
:log-observe              -
:lxd-support              -
:mount-observe            -
:netlink-audit            -
:netlink-connector        -
:network                  -
:network-bind             -
:network-control          -
:network-observe          -
:network-setup-control    -
:network-setup-observe    -
:opengl                   -
:openvswitch-support      -
:physical-memory-control  -
:physical-memory-observe  -
:ppp                      -
:process-control          -
:raw-usb                  -
:removable-media          -
:shutdown                 -
:snapd-control            -
:system-observe           -
:system-trace             -
:time-control             -
:timeserver-control       -
:timezone-control         -
:tpm                      -
:uhid                     -

Notably, the pi2 gadget isn’t providing any slots:

$ snap interfaces pi2
Slot  Plug

How do I access GPIO? Is something missing from the gadget, or am I expected to roll my own if I want to access GPIO (just like serial ports)?

kyrofa 2017-11-29 00:25:50 UTC #2

I don’t see i2c, either. It looks like they’re all specified here at least…

I tried this just in case it was a presentation-layer problem, but no go:

$ sudo snap connect my-snap-name:gpio pi2:bcm-gpio-0
error: snap "pi2" has no slot named "bcm-gpio-0"

@ogra I could use some guidance.

lundmar 2017-11-29 00:40:52 UTC #3

I would also like to see avahi-observe and avahi-control interfaces on the RPI.

ogra 2017-11-29 00:43:14 UTC #4

dont use the stable image until gadget upgrades work …

ogra 2017-11-29 00:47:41 UTC #5

then install the avahi snap, it should provide both …

kyrofa 2017-11-29 00:49:00 UTC #6

@lundmar please open your own topic rather than redirecting my cry for help .

kyrofa 2017-11-29 00:50:07 UTC #7

dont use the stable image until gadget upgrades work …

@ogra ouch, really? I literally just installed this image though. Should I create a new one based on another channel?

Also, while I’m unclear how this could be due to an old gadget since i2c was working back in the 15.04 days, does that mean we should be rolling new stable Ubuntu Core images more regularly?

ogra 2017-11-29 01:00:34 UTC #8

yes, from … http://cdimage.ubuntu.com/ubuntu-core/16/edge/current/

the frequency of image generation does not matter, as long as gadget (and along with that the kernel snap) can not be moved to the stable channel for the pi2/3, we are stuck with the status quo … both snaps need to move over …

kyrofa 2017-11-29 01:01:33 UTC #9

Surely there’s something more stable than edge that has this issue fixed? I’m trying to create another series here, I don’t want to recommend people use edge images.

ogra 2017-11-29 01:06:04 UTC #10

sorry, there is only edge … due to the nature of the pi’s, there is a tie between kernel and gadget and they can only be moved together … but since gadget upgrades do not work (yet ?) installed images might break due to a wrong dtb (old dtb with newer kernel)… this can only move forward once the gadget can be updated on the device…

kyrofa 2017-11-29 01:06:30 UTC #11

Yikes. So we just have broken pi2/3 images and have to live with it? I remember talking about gadget updates in London, do you know the priority of this work (that’s snapd, right?)?

niemeyer 2017-11-29 01:08:47 UTC #12

@kyrofa @ogra We’ve recently investigated this case and there’s actually no real reason to hold these upgrades back. We just need to do the work and cook new images that have a kernel approved by the kernel team.

ogra 2017-11-29 01:09:15 UTC #13

Well, they work, but are missing features …
Not sure where in the core teams schedule gadget/bootloader upgrades are … i know they have been scheduled multiple times over the last year but fell off the schedule due to more urgent bits …

kyrofa 2017-11-29 01:15:17 UTC #14

Thanks @niemeyer. Who’s responsibility is this?

niemeyer 2017-11-29 01:21:41 UTC #15

@kyrofa We’re working together with the kernel team on this, but things changed hands recently in this exact area, so I need to go after it and make sure we have a champion that will take it all the way.

Raspberry Pi 2: Denials using RPi.GPIO

kyrofa 2017-11-29 15:26:14 UTC #16

Alright, thanks @niemeyer. I look forward to that happening. Until then, I’ll start recommending the edge image if anyone needs GPIO.

ogra 2017-11-30 00:42:59 UTC #17

Recommend them to do a:

snap refresh core --stable

right after install … then they at least get the stable core …