trying to catch the bug in usb-support

[Ivan]

Dear friends,

since a couple of days I'm trying to fix some issues concerning the broken support of some usb-devices. I have started with HP ScanJet 4300C usb-scanner. The problem  seems to be rather old (you can look at:
http://lists.freebsd.org/mailman/htdig/freebsd-usb/2005-August/001377.html
http://lists.freebsd.org/mailman/htdig/freebsd-usb/2005-August/001399.html
http://www.freebsd.org/cgi/query-pr.cgi?pr=119018
)
I have tried to attach the scanner on 4.11-STABLE, 7.0-PRERELEASE and now on 8.0-CURRENT. Everywhere the same problem. I have added some debug-output to the uscanner.c and found out, that uaa->iface in uscanner_match() is set to NULL. As I tried to attach the device as ugen, I saw: 

uhub1: port1, set config at addr 2 failed, error=STALLED

I have also tried to set the iface-value explicitly in usb_subr.c by adding:

usbd_device2interface_handle(dev,0,&uaa.iface) 

but also without success.

device_get_ivars() seems to be broken. But what can I do about that? Or what else could be wrong?

I hope someone of you have more experience with that stuff to help me out.


Best regards,
Ivan