Comment 20 for bug 1561474

It seems the problem for me is the action of 'turn off' bluetooth.

I dual boot with Windows 10. If I chose to 'reboot' (not shutdown) from windows and boot into ubuntu, bluetooth will start properly and working fine. The moment I turned off bluetooth it stop working, even reboot again.

I past below the output for command `dmesg|grep -i blue` under the situations of working and not working.

From the dmesg output, it seems different firmware is being loaded for the two cases (revision 0.1 works while revision 0.0 not work). I suspect that the bluetooth daemon modify some of the hardware file when it is turned off. The same for windows 10, I guess it also modifies some hardware file on restart.

================= WORKING CASE ===================
[ 3.393285] Bluetooth: Core ver 2.21
[ 3.393293] Bluetooth: HCI device and connection manager initialized
[ 3.393295] Bluetooth: HCI socket layer initialized
[ 3.393296] Bluetooth: L2CAP socket layer initialized
[ 3.393300] Bluetooth: SCO socket layer initialized
[ 3.403438] Bluetooth: HCI UART driver ver 2.3
[ 3.403439] Bluetooth: HCI UART protocol H4 registered
[ 3.403439] Bluetooth: HCI UART protocol BCSP registered
[ 3.403440] Bluetooth: HCI UART protocol LL registered
[ 3.403440] Bluetooth: HCI UART protocol ATH3K registered
[ 3.403441] Bluetooth: HCI UART protocol Three-wire (H5) registered
[ 3.403491] Bluetooth: HCI UART protocol Intel registered
[ 3.403504] Bluetooth: HCI UART protocol BCM registered
[ 3.403504] Bluetooth: HCI UART protocol QCA registered
[ 3.403505] Bluetooth: HCI UART protocol AG6XX registered
[ 3.478393] Bluetooth: hci0: Firmware revision 0.1 build 68 week 27 2016
[ 4.884372] thinkpad_acpi: rfkill switch tpacpi_bluetooth_sw: radio is unblocked
[ 5.560960] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 5.560961] Bluetooth: BNEP filters: protocol multicast
[ 5.560963] Bluetooth: BNEP socket layer initialized
[ 10.825093] Bluetooth: RFCOMM TTY layer initialized
[ 10.825097] Bluetooth: RFCOMM socket layer initialized
[ 10.825101] Bluetooth: RFCOMM ver 1.11
================= END OF WORKING CASE ===================

================== NOT WORKING CASE =====================
[ 3.536266] Bluetooth: Core ver 2.21
[ 3.536275] Bluetooth: HCI device and connection manager initialized
[ 3.536276] Bluetooth: HCI socket layer initialized
[ 3.536278] Bluetooth: L2CAP socket layer initialized
[ 3.536281] Bluetooth: SCO socket layer initialized
[ 3.546498] Bluetooth: HCI UART driver ver 2.3
[ 3.546499] Bluetooth: HCI UART protocol H4 registered
[ 3.546500] Bluetooth: HCI UART protocol BCSP registered
[ 3.546500] Bluetooth: HCI UART protocol LL registered
[ 3.546501] Bluetooth: HCI UART protocol ATH3K registered
[ 3.546501] Bluetooth: HCI UART protocol Three-wire (H5) registered
[ 3.546532] Bluetooth: HCI UART protocol Intel registered
[ 3.546544] Bluetooth: HCI UART protocol BCM registered
[ 3.546545] Bluetooth: HCI UART protocol QCA registered
[ 3.546545] Bluetooth: HCI UART protocol AG6XX registered
[ 3.632162] Bluetooth: hci0: Bootloader revision 0.0 build 26 week 38 2015
[ 3.633833] Bluetooth: hci0: Device revision is 16
[ 3.633834] Bluetooth: hci0: Secure boot is enabled
[ 3.633835] Bluetooth: hci0: OTP lock is enabled
[ 3.633835] Bluetooth: hci0: API lock is enabled
[ 3.633836] Bluetooth: hci0: Debug lock is disabled
[ 3.633836] Bluetooth: hci0: Minimum firmware build 1 week 10 2014
[ 3.633984] bluetooth hci0: Direct firmware load for intel/ibt-12-16.sfi failed with error -2
[ 3.633985] Bluetooth: hci0: Failed to load Intel firmware file (-2)
[ 3.774670] Bluetooth: hci0: Bootloader revision 0.0 build 26 week 38 2015
[ 3.777812] Bluetooth: hci0: Device revision is 16
[ 3.777813] Bluetooth: hci0: Secure boot is enabled
[ 3.777814] Bluetooth: hci0: OTP lock is enabled
[ 3.777814] Bluetooth: hci0: API lock is enabled
[ 3.777814] Bluetooth: hci0: Debug lock is disabled
[ 3.777815] Bluetooth: hci0: Minimum firmware build 1 week 10 2014
[ 3.777913] bluetooth hci0: Direct firmware load for intel/ibt-12-16.sfi failed with error -2
[ 3.777915] Bluetooth: hci0: Failed to load Intel firmware file (-2)
[ 4.760374] thinkpad_acpi: rfkill switch tpacpi_bluetooth_sw: radio is unblocked
[ 5.455861] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 5.455866] Bluetooth: BNEP filters: protocol multicast
[ 5.455889] Bluetooth: BNEP socket layer initialized
================= END OF NOT WORKING CASE ===================