Nut upsuser - Mar 2008 - distinguishing identical multiple usbhid-ups devices

HI

I would like to connect several Cyberpower Value 800E devices
over a USB hub to a single host. Problem is how to distinguish
them in order to correctly identify because lsusb -vvvv -d  and upsc
show the same device name and serial number is 0

Bus 002 Device 012: ID 0764:0501 Cyber Power System, Inc.
  idVendor           0x0764 Cyber Power System, Inc.
  idProduct          0x0501
  bcdDevice            0.01
  iManufacturer           3 CPS
  iProduct                1 UPS VALUE
  iSerial                 0

usbhid-ups is capable to distinguish devices from the Bus
they are connected to, but as all are at the same hub the bus
is the same. I'd like if usbhid-ups could distinguish them from
the hubbed port they are plugged in.

However different serial number would be great.

Can I somehow reflash the device to change its serial number?

Best regards, Davor

> usbhid-ups is capable to distinguish devices from the Bus
> they are connected to, but as all are at the same hub the bus
> is the same. I'd like if usbhid-ups could distinguish them from
> the hubbed port they are plugged in.
This isn't possible/portable. Only the kernel is aware which physical port
the devices are attached to, but this information is lost when they are
handed off to the libusb layer. At that time, the only thing we have is an
enumerated value, which may (will) change each time you reconnect them. In
practice, this is so unstable that it can't be used.

The only thing that could possibly tell these devices apart (if they don't
have unique serial numbers), is the Bus. So unless you have multiple USB
busses on your system, you're limited to just one UPS of this type. We
can't fix this in NUT.

Best regards, Arjen
-- 
Eindhoven - The Netherlands
Key fingerprint - 66 4E 03 2C 9D B5 CB 9B  7A FE 7E C1 EE 88 BC 57

On Tue, Mar 18, 2008 at 9:39 AM, davor emard <davoremard at gmail.com>
wrote:
>  usbhid-ups is capable to distinguish devices from the Bus
>  they are connected to, but as all are at the same hub the bus
>  is the same. I'd like if usbhid-ups could distinguish them from
>  the hubbed port they are plugged in.
I forget how the bus numbering goes, but what if you added in another
hub between certain devices?

You still are not guaranteed that they will be enumerated in the same
order every time, but at least the device closest to the motherboard
stands a chance of being enumerated first.

-- 
- Charles Lepple

iSerial=0

not only cyberpower unit but also many other manufacturers
have constant serial number in usb interfaces

I can ask cyberpower if they can help me set this serial
number but the chances are small I guess


On 3/18/08, Charles Lepple <clepple at gmail.com>
wrote:
> On Tue, Mar 18, 2008 at 12:58 PM, Ricardo Bugalho <ricardo at lip.pt>
wrote:
> > Hello,
> >  the usbhid driver can distinguish different devices by their serial
> >  number.
> >
> >  Just look for "iSerial" in lsusb -v and add an matching
"serial" in
> >  ups.conf.
>
> Davor already posted the output of lsusb - iSerial is 0.
>
> --
> - Charles Lepple
>
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