I am having this same problem with Logitech m535 bluetooth mouse running Ubuntu 16.04 on a Dell XPS13 9350. Here is the result of the command issued by the OP. Any ideas?

[    2.817422] Bluetooth: Core ver 2.21
[    2.817443] Bluetooth: HCI device and connection manager initialized
[    2.817446] Bluetooth: HCI socket layer initialized
[    2.817449] Bluetooth: L2CAP socket layer initialized
[    2.817455] Bluetooth: SCO socket layer initialized
[    2.826800] Bluetooth: HCI UART driver ver 2.3
[    2.826803] Bluetooth: HCI UART protocol H4 registered
[    2.826805] Bluetooth: HCI UART protocol BCSP registered
[    2.826806] Bluetooth: HCI UART protocol LL registered
[    2.826807] Bluetooth: HCI UART protocol ATH3K registered
[    2.826809] Bluetooth: HCI UART protocol Three-wire (H5) registered
[    2.826843] Bluetooth: HCI UART protocol Intel registered
[    2.826858] Bluetooth: HCI UART protocol BCM registered
[    2.826859] Bluetooth: HCI UART protocol QCA registered
[    2.960951] Bluetooth: hci0: BCM: chip id 110
[    2.977372] Bluetooth: hci0: BCM4350C5
[    2.977947] Bluetooth: hci0: BCM (003.006.007) build 0000
[    2.979162] bluetooth hci0: Direct firmware load for brcm/BCM-0a5c-6412.hcd failed with error -2
[    2.979168] Bluetooth: hci0: BCM: Patch brcm/BCM-0a5c-6412.hcd not found
[    4.068669] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[    4.068672] Bluetooth: BNEP filters: protocol multicast
[    4.068676] Bluetooth: BNEP socket layer initialized
[    6.370274] Bluetooth: RFCOMM TTY layer initialized
[    6.370281] Bluetooth: RFCOMM socket layer initialized
[    6.370285] Bluetooth: RFCOMM ver 1.11
[   43.979826] Bluetooth: hci0: BCM: chip id 110
[   43.995724] Bluetooth: hci0: BCM4350C5
[   43.996692] Bluetooth: hci0: BCM (003.006.007) build 0000
[   43.996725] bluetooth hci0: Direct firmware load for brcm/BCM-0a5c-6412.hcd failed with error -2
[   43.996727] Bluetooth: hci0: BCM: Patch brcm/BCM-0a5c-6412.hcd not found
[  368.022543] Bluetooth: HIDP (Human Interface Emulation) ver 1.2
[  368.022566] Bluetooth: HIDP socket layer initialized
[  370.269291] input: Bluetooth Mouse M336/M337/M535 as /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/bluetooth/hci0/hci0:12/0005:046D:B014.0002/input/input19
[  370.270218] hid-generic 0005:046D:B014.0002: input,hidraw1: BLUETOOTH HID v12.00 Mouse [Bluetooth Mouse M336/M337/M535] on 30:52:cb:85:2c:ec
[ 1269.884899] Bluetooth: hci0 urb ffff8802731c2c00 failed to resubmit (2)
[ 1280.112502] Bluetooth: hci0: BCM: chip id 110
[ 1280.128489] Bluetooth: hci0: ChromeLinux_658B
[ 1280.129363] Bluetooth: hci0: BCM (003.006.007) build 0000
[ 1280.129420] bluetooth hci0: Direct firmware load for brcm/BCM-0a5c-6412.hcd failed with error -2
[ 1280.129429] Bluetooth: hci0: BCM: Patch brcm/BCM-0a5c-6412.hcd not found
[ 1284.690426] input: Bluetooth Mouse M336/M337/M535 as /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/bluetooth/hci0/hci0:11/0005:046D:B014.0003/input/input20
[ 1284.691111] hid-generic 0005:046D:B014.0003: input,hidraw1: BLUETOOTH HID v12.00 Mouse [Bluetooth Mouse M336/M337/M535] on 30:52:cb:85:2c:ec
[ 4944.970706] input: Bluetooth Mouse M336/M337/M535 as /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/bluetooth/hci0/hci0:12/0005:046D:B014.0004/input/input21
[ 4944.971018] hid-generic 0005:046D:B014.0004: input,hidraw1: BLUETOOTH HID v12.00 Mouse [Bluetooth Mouse M336/M337/M535] on 30:52:cb:85:2c:ec
[    0.206465] [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored
[    2.979162] bluetooth hci0: Direct firmware load for brcm/BCM-0a5c-6412.hcd failed with error -2
[    3.084004] brcmfmac 0000:3a:00.0: Direct firmware load for brcm/brcmfmac4350-pcie.txt failed with error -2
[    3.497260] brcmf_c_preinit_dcmds: Firmware version = wl0: Oct 22 2015 06:16:26 version 7.35.180.119 (r594535) FWID 01-e791c176
[   43.977871] brcmfmac 0000:3a:00.0: Direct firmware load for brcm/brcmfmac4350-pcie.txt failed with error -2
[   43.996725] bluetooth hci0: Direct firmware load for brcm/BCM-0a5c-6412.hcd failed with error -2
[   44.410839] brcmf_c_preinit_dcmds: Firmware version = wl0: Oct 22 2015 06:16:26 version 7.35.180.119 (r594535) FWID 01-e791c176
[ 1280.129420] bluetooth hci0: Direct firmware load for brcm/BCM-0a5c-6412.hcd failed with error -2
bluetooth             520192  36 bnep,hidp,btbcm,btqca,btrtl,btusb,hci_uart,rfcomm,btintel