Re: [pyusb-users] USB topology

[Nicolas P. <nic...@aa...>]

Le 13/05/2016 à 15:10, Jeffrey Nichols a écrit :
> On 5/13/2016 9:03 AM, Nicolas Pinault wrote:
>> Le 12/05/2016 à 17:15, Wander Lairson Costa a écrit :
>>> 2016-05-12 11:40 GMT-03:00 Nicolas Pinault<nic...@aa...>:
>>>> Hi,
>>>>
>>>> Is it possible to retrieve USB bus topology with PyUSB ?
>>>>
>>> Yes, you will need to use the Device object "port_number" and "bus" properties.
>> While it is enough for my application, I don't see how to reconstruct 
>> the USB tree with just "port_number".
> There's also "port_numbers", assuming you're using a somewhat recent 
> libusb-1.0 version as your backend. Combine that with the bus 
> attribute, and you can get a representation of the physical attachment 
> point of the device.
I already tried to use "port_numbers" but this field was always blank.
After updating libusb-1.0, this field is not blank anymore.

What  I don't understand is that bus/port_number numbers are not unique.
On my system :
   IdVendor8086 IdProduct=1E26 bus=1 Address=1 port=0
   IdVendor8086 IdProduct=1E2D bus=2 Address=1 port=0
* IdVendor0204 IdProduct=6025 bus=1 Address=6 port=1 ports = (1, 6, 1)
   IdVendor0424 IdProduct=2513 bus=1 Address=2 port=6 ports = (1, 6)
+ IdVendor046D IdProduct=C061 bus=2 Address=5 port=1 ports = (1, 1)
   IdVendor0529 IdProduct=0001 bus=1 Address=4 port=5 ports = (1, 5)
   IdVendor2CFF IdProduct=0002 bus=1 Address=5 port=2 ports = (1, 6, 2)
   IdVendor413C IdProduct=2107 bus=2 Address=2 port=2 ports = (1, 2)
+ IdVendor8087 IdProduct=0024 bus=2 Address=4 port=1 ports = (1,)
* IdVendor8087 IdProduct=0024 bus=1 Address=3 port=1 ports = (1,)
   IdVendor8564 IdProduct=4000 bus=3 Address=20 port=8 ports = (8,)
   IdVendor8086 IdProduct=1E31 bus=3 Address=1 port=0

The lines marked with a + or a * contains same bus/port_number numbers.
Only port_numbers field is different.
What does this mean ?

Regards,
Nicolas



>
> Jeff
>
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-- 
*Nicolas PINAULT
R&D electronics engineer
*** ni...@aa... <mailto:ni...@aa...>

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