Comment 4 for bug 1423266

Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/headset.c:headset_set_state() State changed /org/bluez/859/hci0/dev_00_21_CC_E9_02_39: HEADSET_STATE_CONNECTED -> HEADSET_STATE_PLAY_IN_PROGRESS
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/media.c:headset_state_changed()
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_request_create() Request created: method=Acquire id=1
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_owner_add() Owner :1.46 Request Acquire
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_transport_add() Transport /org/bluez/859/hci0/dev_00_21_CC_E9_02_39/fd0 Owner :1.46
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: Operation not supported (95)
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_transport_remove() Transport /org/bluez/859/hci0/dev_00_21_CC_E9_02_39/fd0 Owner :1.46
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_transport_release() Transport /org/bluez/859/hci0/dev_00_21_CC_E9_02_39/fd0: read lock released
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_transport_release() Transport /org/bluez/859/hci0/dev_00_21_CC_E9_02_39/fd0: write lock released
Feb 18 17:16:19 ubuntu-phablet bluetoothd[859]: audio/transport.c:media_request_reply() Request Acquire Reply Input/output error

^^^

So it basically failed on request acquire, with a bad input/output error from the driver side. Could be a combination of kernel/driver/hardware, so it might need so further investigation on the kernel side.