I will try to give complete information, but please let me know if I leave anything out.
Currently, I can use the headset (which is a Sennheiser HD 4.50BTNC) when A2DP Sink mode is selected in Sound settings, but this does allow for 2-way communication. When I select HSP/HFP all audio stops playing.
I am running Linux Mint 18.2. The bluetooth adapter shows up in lsusb as the following:
Bus 001 Device 010: ID 0a5c:21e8 Broadcom Corp. BCM20702A0 Bluetooth 4.0
dmesg | egrep -i 'blue|firm' prints:
I've tried installing the firmware found here:[ 0.193557] ACPI: [Firmware Bug]: BIOS _OSI(Linux) query ignored
[ 16.622052] Bluetooth: Core ver 2.21
[ 16.622058] Bluetooth: HCI device and connection manager initialized
[ 16.622060] Bluetooth: HCI socket layer initialized
[ 16.622061] Bluetooth: L2CAP socket layer initialized
[ 16.622067] Bluetooth: SCO socket layer initialized
[ 16.836259] Bluetooth: HCI UART driver ver 2.3
[ 16.836260] Bluetooth: HCI UART protocol H4 registered
[ 16.836261] Bluetooth: HCI UART protocol BCSP registered
[ 16.836261] Bluetooth: HCI UART protocol LL registered
[ 16.836261] Bluetooth: HCI UART protocol ATH3K registered
[ 16.836261] Bluetooth: HCI UART protocol Three-wire (H5) registered
[ 16.836279] Bluetooth: HCI UART protocol Intel registered
[ 16.836284] Bluetooth: HCI UART protocol BCM registered
[ 16.836284] Bluetooth: HCI UART protocol QCA registered
[ 16.836284] Bluetooth: HCI UART protocol AG6XX registered
[ 62.271654] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 62.271655] Bluetooth: BNEP filters: protocol multicast
[ 62.271657] Bluetooth: BNEP socket layer initialized
[ 94.654115] Bluetooth: hci0: BCM: chip id 63
[ 94.670102] Bluetooth: hci0: BCM20702A
[ 94.671030] Bluetooth: hci0: BCM20702A1 (001.002.014) build 0000
[ 97.015706] Bluetooth: hci0 command 0x213c tx timeout
[ 104.951751] Bluetooth: hci0: BCM: Patch command 213c failed (-110)
[ 106.999775] Bluetooth: hci0 command 0x0c03 tx timeout
[ 115.191898] Bluetooth: hci0: BCM: Reset failed (-110)
[ 117.207891] Bluetooth: hci0 command 0x0c03 tx timeout
[ 125.432011] Bluetooth: hci0: BCM: Reset failed (-110)
[ 197.467097] Bluetooth: hci0: BCM: chip id 63
[ 197.483094] Bluetooth: hci0: BCM20702A
[ 197.484093] Bluetooth: hci0: BCM20702A1 (001.002.014) build 0000
[ 197.484121] bluetooth hci0: Direct firmware load for brcm/BCM20702A1-0a5c-21e8.hcd failed with error -2
[ 197.484124] Bluetooth: hci0: BCM: Patch brcm/BCM20702A1-0a5c-21e8.hcd not found
[ 197.598069] Bluetooth: RFCOMM TTY layer initialized
[ 197.598076] Bluetooth: RFCOMM socket layer initialized
[ 197.598085] Bluetooth: RFCOMM ver 1.11
https://plugable.com/2014/06/23/plugabl ... -on-linux/
But once that is done, the bluetooth adapter stops working and gets stuck on "Searching for devices...". I deleted the firmware file and bluetooth worked again.
Thanks for your help.