On Tue, Sep 13, 2016 at 07:20:01PM +0530, Ajay Garg wrote:
> Ahhhh..... (sorry for my stupid realisation-originated-question), for
> the same serial-cable types with identical "idVendor" and "idProduct",
> are they guaranteed to have unique serial-numbers?
No, there is no such USB requirement. Odds are, if it is a cheap
device, the serial numbers will all be the same.
> We have the Prolific-PL2303-Serial-To-USB-converters with ID 067b:2303.
> Right now I have two of these pieces, and they have identical 067b:2303, but
>
> udevadm info -a -n /dev/ttyUSB0 | grep '{serial}' | head -n1
>
> gives different serial-numbers for these two pieces.
Oh nice, you have some "good" ones :)
> Can I generalize this to any piece of the same cable-type?
Nope :(
That's why you should use /dev/serial/ it should give you something you
can use, even if the serial numbers are identical.
good luck!
greg k-h
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