USB & Sysfs Question ( posible issue )

[Razvan Gavril]

If i had a usb-serial device in linux, i can/could find a symlink in 
/sys/bus/usb-serial/devices named ttyUSBX that is/was pointing to 
another sysfs directory, which is in /sys/device. The directory in the 
/device looked something like this : 
/devices/pci0000:00/0000:00:02.0/usb1/1-3/1-3:1.0/ttyUSBX . As far i 
could figure out the '... usb1/1-3/...' part from the path means that 
the device is connected to the port 3 of the 1st usb controler.

I used this for a long of time to uniquely identify phisical usb ports 
from a computer, when upgrading to 2.6.17, something strange started to 
happen: even if i didn't remove the usb device from a specified port of 
a the computer, sometimes when rebooting the usb controlers changed 
their numbers in sysfs. A device that was before the reboot 
'...usb1/1-3/...' can be now ' ...usb2/2-3...' or '...usb4/4-3...'.

The main idea is that an usb port can't no loger be identified only by 
looking on it's sysfs path. Is this a normal behavior ? I'm asking this 
as i didn't get this numbering change when using older 2.6 kernel.

Thanks

--
Razvan Gavril
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