continuing reboot with usb devices inserted

Hi, it's some months (i know i should investigate before but the pc is
always on ;-)
i've got this strange and  very annoying behaviour.

I'm running 4.0_BETA2, kernel generic, amd64.

If i attach my usb mouse or my usb external hd after booting the pc i
could use them without any kind of problem

uhidev0 at uhub1 port 2 configuration 1 interface 0
uhidev0: Logitech USB Receiver, rev 1.10/9.10, addr 2, iclass 3/1
ums0 at uhidev0: 5 buttons and Z dir.
wsmouse0 at ums0 mux 0

umass0 at uhub4 port 3 configuration 1 interface 0
umass0: Maxtor Corporation Maxtor 3200, rev 2.00/0.01, addr 2
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
sd0 at scsibus0 target 0 lun 0: <Maxtor, 3200, 0344> disk fixed
sd0: fabricating a geometry
sd0: 298 GB, 305245 cyl, 64 head, 32 sec, 512 bytes/sect x 625142448 sectors

if only i try to reboot the system with an usb device attached my box
just keeps on rebooting

don't know where to start..

luca
-- 
ascolta  http://radio.sironi.tk