Hi, Back when I was using just the J1939 branch (before it got re-written and mainlined), I was able to receive and transmit multi-frame messages. Upgrading to kernel v5.4, this is no longer the case. For the receive part, it is failing in j1939_tp_im_involved_anydir() call, which is the first thing called by j1939_tp_recv(). The socket is set to promiscuous mode; has no problem receiving ALL the 8-byte long messages but fails on longer ones. There should not be any difference with how the socket is setup as far as the message length goes but is there a new step needed in order to receive the multi-frame messages as well? The same question applies for the transmit side. Thanks for the help! --elenita
