Nut upsuser - Oct 2023 - usbhid-ups not loading with Arduino Leonardo on Ubuntu 23.10

> 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

>  VID 2341 doesn't show up in the NUT Git source tree.
I was curious about this so just searched for Arduino and then 2341. I
found a few hits, but the interesting one was  in nut/drivers
/arduino-hid.c

I don't know enough about the project to know what a "subdriver"
(that's
what the comments says) is, but it looks to me like there's at least some
people that have thought about Arduino support since 2021.

Is it possible I need to compile NUT myself instead of using the Ubuntu
package?


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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