I do some very simple LAPDm test.
Establishing link.
ms_to_bts_l1_cb: MS(us) -> BTS prim message
bts_to_ms_tx_cb: MS->BTS(us) message 29
BTS: Verifying CM request.

Confirming
ms_to_bts_tx_cb: BTS->MS(us) message 9
MS: Verifying incoming primitive.

Sending back to MS
ms_to_bts_tx_cb: BTS->MS(us) message 12
MS: Verifying incoming MM message: 3
ms_to_bts_l1_cb: MS(us) -> BTS prim message

Sending back to BTS
ms_to_bts_l1_cb: MS(us) -> BTS prim message
bts_to_ms_tx_cb: MS->BTS(us) message 14
BTS: Verifying dummy message.
Success.