What priority of hotplug support getting?

Hi all,

I’d like to enquire what priority hot-plug device tracking has in snapd?

LP: #1606674 is the bug I’m mostly referring to here since it impacts Node-RED, they are unable to interface with many common USB devices that are exposed as serial devices. I see @kyrofa and @mhall119 have encountered similar issues.

Is there any chance this can get some attention?


Yeah I definitely have a vested interest in this question, thanks for asking!

We have a sprint at the end of the month to discuss our upcoming agenda, and this is a great topic to be covered there. I’ll keep it in mind and circle back in this topic after we have a better position.


A bit late, but for the record we haven’t managed to spend time on this in the last few months. Feature is still in the roadmap, but not scheduled right now.

@kyrofa @Wimpress We should probably have a call to discuss the use cases so we can have a better idea of how to prioritize the feature.

@niemeyer Node-RED have made it clear that they will not publish the Node-RED snap to the stable channel until serial port access on classic distros is possible. They are requesting the following serial device access from classic distros:

Must have

The minimum they require is accessing whatever hardware the computer comes with that exposes a serial port , and this includes /dev/ttyS{0-9} and /dev/ttyACM{0-9} for the Raspberry Pi as far as they are concerned. With this access available they will publish Node-RED in stable.

Nice to have

Ideally they would also like access to /dev/ttyUSB{0-9}, but publishing Node-RED to stable is not conditional on this.

@kyrofa I’d be interested to hear how this compares with the must have requirements for ROS.

Do they want access to all serial ports at once, or a specific serial port? For all serial ports at once, hotplug doesn’t help as it will create an individual serial-port interface mapping each specific port available.

The hotplug feature is scheduled for after the current work on interface hooks is completed.

Given what Node-RED is, I suspect they’ll want access to the whole set of ports.

The ROS use-cases of which I’m aware typically need access to a few serial ports, determined by USB vendor/product IDs. Basically, the way the gadget exposes them is acceptable, except that it’s in the gadget. Which means it doesn’t work on classic, and requires a custom gadget on core (which isn’t the most user-friendly thing). Being able to do something similar to that in the snap itself (which worked on both classic and core) would be great, whether that’s via the hotplug interface or something else.

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