[Nut-upsuser] usbhid-ups not loading with Arduino Leonardo on Ubuntu 23.10

[Kelly Byrd]

> Here you're referring to just making things work on Windows or macOS,
right? I don't think it will be quite as simple with NUT, mostly because
the NUT drivers are trying to expose all of the variables and commands,
rather than just the simple shutdown bits.

By "work with on Windows on macOS" I mean: "both Windows and MacOS show the
correct "AC present/charging vs "no AC/discharging" status as well as
showing the expected remaining status and percent charged.

> I'm not sure where a generic HID PDC driver sits in the priority list at
the moment, but IIRC the current driver is still fairly tightly coupled to
the USB VID and resulting model-specific mappings

> f you change the VID/PID to something supported already, things just
might work...

The current usbhid-ups driver should be perfect. As I said in the original
email, rhe Ubuntu package includes a usev rules file that has a VID/PID
(2341:8036) for the Arduino I have so it looks supported to me and that
should solve the permissions issue, right?   The USB HID power device
standard has a well known report structure so I expected the simple things
like "AC Present" vs "Discharding" to work. But I'm not even at mapping
variables yet. Just at: "the OS package appears to support thie VID/PID,
but it doesn't work"





On Sun, Oct 29, 2023 at 6:46 PM Charles Lepple <clepple at gmail.com> wrote:

> > On Oct 29, 2023, at 9:25 PM, Kelly Byrd <kbyrd at memcpy.com> wrote:
> >
> > I have seen reports of folks claiming this just worked for them out of
> the box,
>
> Here you're referring to just making things work on Windows or macOS,
> right? I don't think it will be quite as simple with NUT, mostly because
> the NUT drivers are trying to expose all of the variables and commands,
> rather than just the simple shutdown bits.
>
> I'm not sure where a generic HID PDC driver sits in the priority list at
> the moment, but IIRC the current driver is still fairly tightly coupled to
> the USB VID and resulting model-specific mappings. So once you get the
> permissions worked out, you would still need a new source file that maps
> the HID Usage "paths" to NUT variable names. It's one of those things that
> in hindsight, it would have been great to fall back to a generic mapping
> that just looks at the OB and LB bits, but real-world UPSes are messy, and
> we would have needed those model-specific mappings to be able to
> distinguish things like input and output voltage.
>
> That said, if you change the VID/PID to something supported already,
> things just might work. The "Couldn't retrieve descriptors" is likely a
> result of the driver dropping root privileges, then not having enough
> permissions to write to the /dev/bus/usb node to request the HID
> descriptor. I don't know how your VID/PID got into the udev rules file -
> VID 2341 doesn't show up in the NUT Git source tree.
>
> --
> Charles Lepple
> clepple at gmail
>
>
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