Hey Roland/IB experts,

I'm playing around with XRC using mlx4, and I'm hitting an error. 
Attached is the program to setup an XRC connection and exchange some 
data.  It is based on the upstream XRC sample program submitted by 
Intel.  But I back-ported it to the OFED-1.5.4.1 XRC API.  The QPs seem 
to get setup ok, with the target xrc QP in RTR and the initiator QP in 
RTS.  Then the server side (initiator QP) posts a send to the client's 
XRC-SRQ.  On ingress, the client mlx driver gets a type 
MLX4_EVENT_TYPE_WQ_ACCESS_ERROR (0x11) subtype 0 event which flows up to 
the app via the async event channel as an IBV_EVENT_QP_ACCESS_ERR event.

I'm wondering where to look for the problem?  I think I have 
dest_qp_num, sq_psn and rq_psn setup correctly, so I'm not sure what I'm 
doing wrong.  Any thoughts/ideas is much appreciated!

Here's the client output:

[root@hpc-hn1 libibverbs-1.1.4]# ibv_xsrq_pingpong -d mlx4_0 192.168.174.52
    local: LID 0001, QPN RECV 98004b SEND 18004c, PSN 5b6d99, SRQN 0042
   remote: LID 0002, QPN RECV d4004a SEND 54004b, PSN d7ba7a, SRQN 0042
XRC event_type IBV_EVENT_QP_ACCESS_ERR (0x3), arg 0x98004b
XRC RCV QP: rq_psn 0xd7ba7a sq_psn 0 dest_qp_num 0x54004b access_flags 0x6
XRC event_type IBV_EVENT_QP_LAST_WQE_REACHED (0x10), arg 0x98004b
XRC RCV QP: rq_psn 0xd7ba7a sq_psn 0 dest_qp_num 0x54004b access_flags 0x6

Server output:

[root@hpc-cn2 libibverbs-1.1.4]# ibv_xsrq_pingpong  -d mlx4_0
   remote: LID 0001, QPN RECV 98004b SEND 18004c, PSN 5b6d99, SRQN 0042
    local: LID 0002, QPN RECV d4004a SEND 54004b, PSN d7ba7a, SRQN 0042