[Nut-upsuser] NUT 2.4.3 on new server can not see serial number, but old nut on different hardware can?

[Charles Lepple]

On Nov 12, 2010, at 11:16 AM, Jon Bendtsen wrote:

> dkplugbab9:/usr/local/ups/etc# /usr/local/ups/bin/usbhid-ups -a  
> apc1500 -u nut -DD
> Network UPS Tools - Generic HID driver 0.34 (2.4.3)
> USB communication driver 0.31
>   0.000000	debug level is '2'
>   0.002738	upsdrv_initups...
>   0.005059	Checking device (051D/0002) (001/011)
>   0.005304	- VendorID: 051d
>   0.005351	- ProductID: 0002
>   0.005383	- Manufacturer: unknown
>   0.005420	- Product: unknown
>   0.005451	- Serial Number: unknown
>   0.005486	- Bus: 001
>   0.005516	Trying to match device
>   0.005630	Device does not match - skipping

Arjen has a point about a lot of things changing at once, but one  
thing that can cause these items to show up as "unknown" is that the  
"nut" user doesn't have write access to the device.

In order to fetch a string from a USB device (such as the serial  
number), you need to be able to write a control message to it.

On the old system, the Debian packaging would have interacted with  
udev to set this up. Chances are that you just need to find the right  
place to drop the scripts/udev/nut-usbups.rules file, and tell udev to  
rescan the bus.