[ofa-general] Making NOSRQ RFC 4755 compliant

[Pradeep Satyanarayana]

I am in the process of developing a patch to make the NOSRQ RFC 4755 
compliant. I am trying to test this patch with a hack. The hack enables
the passive side to send to the tx_qp of the active side.

I am trying to ping the passive side and I find that the packet does get to
the active side. However, I see that the passive side gets a retry exceeded 
error. I have ensured that the passive side is indeed sending to the correct 
qp (i.e. tx_qp of the active side), the psn is set to 0 (for now). I also verified
that the pkey is set to the default 0xffff (implying full membership), by 
looking in /sys/class/infiniband/ehca0/ports/1/pkeys/0. For RC qkey should not 
be an issue.

My suspicion is that the reply from the passive side is being dropped on the active
side (for some unknown reason). And that is why the passive side sees a retry 
exceeded error. 

>From the IB spec I can't see anything that I am missing unless the packet
on the active side is being dropped because of a failed packet header validation.

Should I be looking at some other parameters? Any suggestions to debug this problem
would be helpful.

Pradeep