Access rights for specific USB device in /dev? (Was: Ippon UPS over USB (ugen1.2: <Cypress Semiconductor> at usbus1)?)

Lev Serebryakov lev at
Tue Aug 2 23:31:08 UTC 2011

Hello, Freebsd-usb.
You wrote 3 августа 2011 г., 2:37:09:

>   Now I have another question: devfs(8) uses device types or paths to
> specify access rules for /dev/*, which is bad idea for USB device, as
> it will change path when cable will be re-attached to another port. Is
> here any method to set owner:group of device node by VID/PID or ID
> string or something like this?
 I've tried to add "attach" rule to devd.conf, but here is one
problem: $device-name is "ugen1.2" for example, and "devfs" change
owner and permissions on /dev/ugen1.2, but it is only "symbolic link"
and real device is "/dev/usb/1.2.0" in such case -- as result, owner
and permissions on real device stay unchanged and "blazer_usb" can not
access it again :(

// Black Lion AKA Lev Serebryakov <lev at>

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