$ dmesg | grep -i blue
[    2.349206] usb 1-5: Product: Bluetooth Radio
[    5.654118] thinkpad_acpi: rfkill switch tpacpi_bluetooth_sw: radio is blocked
[    6.921580] Bluetooth: Core ver 2.22
[    6.921599] Bluetooth: HCI device and connection manager initialized
[    6.921602] Bluetooth: HCI socket layer initialized
[    6.921604] Bluetooth: L2CAP socket layer initialized
[    6.921607] Bluetooth: SCO socket layer initialized
[    7.243154] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[    7.243155] Bluetooth: BNEP filters: protocol multicast
[    7.243158] Bluetooth: BNEP socket layer initialized
[    8.956016] Bluetooth: hci0: command 0x1001 tx timeout
[   17.116414] Bluetooth: hci0: HCI_OP_READ_LOCAL_VERSION failed (-110)
[   29.010025] Modules linked in: twofish_generic twofish_avx_x86_64 twofish_x86_64_3way twofish_x86_64 twofish_common serpent_avx2 serpent_avx_x86_64 serpent_sse2_x86_64 serpent_generic blowfish_generic blowfish_x86_64 blowfish_common cast5_avx_x86_64 cast5_generic cast_common des_generic algif_skcipher camellia_generic ablk_helper camellia_x86_64 lrw glue_helper xcbc md4 algif_hash af_alg xfrm_user xfrm4_tunnel tunnel4 ipcomp xfrm_ipcomp esp4 ah4 af_key xfrm_algo xt_tcpudp iptable_filter bnep btusb btrtl btbcm btintel bluetooth ecdh_generic uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev media snd_soc_skl snd_soc_skl_ipc snd_hda_ext_core snd_soc_sst_dsp snd_soc_sst_ipc snd_soc_acpi snd_soc_core snd_hda_codec_hdmi snd_compress snd_hda_codec_conexant snd_hda_codec_generic
$ lsmod | grep blue
bluetooth             544768  12 btrtl,btintel,bnep,btbcm,btusb
ecdh_generic           24576  1 bluetooth

$ hciconfig
hci0:        Type: Primary  Bus: USB
        BD Address: 00:00:00:00:00:00  ACL MTU: 0:0  SCO MTU: 0:0
        DOWN
        RX bytes:0 acl:0 sco:0 events:0 errors:0
        TX bytes:0 acl:0 sco:0 commands:1 errors:1