[ofa-general] Non-Signaled RDMA Read (cxgb3)

[Steve Wise]

Roland Dreier wrote:
>  > I am trying to post a non-signaled RDMA Read WR. Somehow OFED 1.3 running 
>  > on a T3 Chelsio Adapter seems
>  > not to care what I set for 'enum ibv_send_flags' in my 'struct 
>  > ibv_send_wr'. I always get a work completion with status
>  > set to IBV_WC_SUCCESS and opcode IBV_WC_RDMA_READ. When creating the 
>  > 'struct ibv_qp' I have set
>  > 'sq_sig_all = 0' in 'struct ibv_qp_init_attr'. With RDMA Write and Send I 
>  > do not get a WC when I set the 'ibv_send_flags'
>  > to 0.
>  > 
>  > What am I missing here?
>
> Looks like you're hitting this -- the cxgb3 driver has:
>
>                 case IB_WR_RDMA_READ:
>                         t3_wr_opcode = T3_WR_READ;
>                         t3_wr_flags = 0; /* T3 reads are always signaled */
>
> so I guess the HW can't do unsignaled RDMA reads.
>
>  - R.
>   
Right.  This is a T3 hw limitation.  It will be fixed in the next chip.

Steve.