Comment 288 for bug 268502

Same issue with usb BT dongle from Cambridge Silicon Radio (0a12:0001) and kernel 2.6.31 (x86_64 arch).

$ uname -a
Linux oem-desktop 2.6.31-22-generic #60-Ubuntu SMP Thu May 27 02:41:03 UTC 2010 x86_64 GNU/Linux

$ lsusb
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 003: ID 05e3:0716 Genesys Logic, Inc.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 004: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 004 Device 002: ID 046d:c517 Logitech, Inc. LX710 Cordless Desktop Laser
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

$sudo dpkg -l |grep bluetooth
ii bluetooth 4.51-0ubuntu2 Bluetooth support
ii gnome-bluetooth 2.28.1-0ubuntu2 GNOME Bluetooth tools
ii libbluetooth3 4.51-0ubuntu2 Library to use the BlueZ Linux Bluetooth sta
ii libgnome-bluetooth7 2.28.1-0ubuntu2 GNOME Bluetooth tools - support library
ii pulseaudio-module-bluetooth 1:0.9.19-0ubuntu4.1 Bluetooth module for PulseAudio sound server

$ hcitool scan
Scanning ...
Inquiry failed: Connection timed out

$tail /var/log/kern.log
Aug 3 19:59:38 oem-desktop kernel: [ 194.740037] usb 4-4: new full speed USB device using ohci_hcd and address 4
Aug 3 19:59:38 oem-desktop kernel: [ 194.966352] usb 4-4: configuration #1 chosen from 1 choice
Aug 3 20:01:26 oem-desktop kernel: [ 302.647758] hci_cmd_task: hci0 command tx timeout
Aug 3 20:02:35 oem-desktop kernel: [ 371.505141] hci_cmd_task: hci0 command tx timeout