$ hcitool scan
Device is not available: No such device
$ lsusb
...
Bus 001 Device 009: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
...
$ hciconfig dev
hci0:   Type: BR/EDR  Bus: USB
        BD Address: 00:1B:10:00:2A:EC  ACL MTU: 1017:8  SCO MTU: 64:0
        DOWN
        RX bytes:1355 acl:0 sco:0 events:49 errors:0
        TX bytes:204 acl:0 sco:0 commands:48 errors:0
$ hciconfig -a
hci0:   Type: BR/EDR  Bus: USB
        BD Address: 00:1B:10:00:2A:EC  ACL MTU: 1017:8  SCO MTU: 64:0
        DOWN
        RX bytes:1355 acl:0 sco:0 events:49 errors:0
        TX bytes:204 acl:0 sco:0 commands:48 errors:0
        Features: 0xff 0xff 0x8d 0xfe 0x9b 0xf9 0x00 0x80
        Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
        Link policy:
        Link mode: SLAVE ACCEPT
$ hcitool dev
Devices:
$ sudo hciconfig hci0 piscan
Can't set scan mode on hci0: Network is down (100)
$ sudo hciconfig hci0 reset
Can't init device hci0: Operation not supported (95)
$ /etc/init.d/bluetooth status
[ ok ] bluetooth is running.
$ sudo bluez-simple-agent
Traceback (most recent call last):
  File "/usr/bin/bluez-simple-agent", line 104, in <module>
    path = manager.DefaultAdapter()
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 70, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 145, in __call__
    **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 651, in call_blocking
    message, timeout)
dbus.exceptions.DBusException: org.bluez.Error.NoSuchAdapter: No such adapter