Hi everyone, I'm trying to understand and narrow down a pairing problem with this controller that I'm trying to make it work in Linux. When pairing, the negotiation does not complete and the system logs the following messages: Bluetooth: hci0: unexpected SMP command 0x08 from dd:5e:b9:fe:49:3f Bluetooth: hci0: unexpected SMP command 0x09 from dd:5e:b9:fe:49:3f Bluetooth: hci0: Opcode 0x200d failed: -110 Bluetooth: hci0: request failed to create LE connection: err -110 (dd:5e:b9:fe:49:3f is my bluetooth mouse) After some debug I found the condition that refuses the SMP commands and drops them: net/bluetooth/smp.c in smp_sig_channel() if (smp && !test_and_clear_bit(code, &smp->allow_cmd)) goto drop; The interesting part is that if I disable this condition with comments, the pairing process manages to complete and my bluetooth mouse starts to work (even with some errors in logs): Bluetooth: hci0: Opcode 0x200d failed: -110 Bluetooth: hci0: request failed to create LE connection: err -110 hid: raw HID events driver (C) Jiri Kosina input: Logi M650 L Mouse as /devices/virtual/misc/uhid/0005:046D:B02A.0001/ input/input6 hid-generic 0005:046D:B02A.0001: input,hidraw0: BLUETOOTH HID v0.09 Mouse [Logi M650 L] on f4:4e:fc:c0:de:5e Bluetooth: hci0: Opcode 0x200d failed: -110 Bluetooth: hci0: request failed to create LE connection: err -110 Logs from bluetoothd receiving the mouse data events: bluetoothd[576]: src/shared/att.c:can_read_data() (chan 0x55f8ad8db380) ATT PDU received: 0x1b bluetoothd[576]: src/shared/att.c:can_read_data() (chan 0x55f8ad8db380) ATT PDU received: 0x1b bluetoothd[576]: src/shared/att.c:can_read_data() (chan 0x55f8ad8db380) ATT PDU received: 0x1b I kindly ask guidance on what could be done in these cases or any hints how to further debug this issue. For context, the controller works in other systems using generic drivers. Regards, Raul.