I have a new laptop, a Compaq R3000Z (AMD64, but currently running a
32 bit kernel).  It has a built-in USB Bluetooth device, which
identifies itself as ID 049f:0086.  It works great with the hci_usb
driver from boot.

The laptop also has a "wireless enable/disable" switch, which is a
hardware switch that when pressed drops power to the internal 802.11b
antenna and (apparently) disconnects the HCI controller from the USB
bus.  When I use this, I get a 100% repeatable oops in the hci_usb
driver.  The driver then locks up and refuses to unload, although the
rest of the kernel appears to be unaffected.

Andy