[openib-general] Unusable QP's on CM established connections from gen2 client to gen1 server.

[Bub Thomas]

Sean,
you got it! 
Setting the hop_limit from 64 down to 0 or 1 solved the problem. :-)
Don't ask me where I got that hop_limit from, it must have been an
example I found somewhere.
Can you explain why that hop_limit/is_global makes a difference in
communication between gen1 and gen2? Does the counterpart need to have
the same hop_limit?
The path record values I use are queried from the OSM using a
SERVICE_RECORD query followed by a path record query.
I'm not using any alternate path record values, is this critical?
In addition I enclose the values I path into the ib_cm_sned_req call.
Can you pls have a look if you find something alse looking abnormal.
Thanks
Thomas Bub

    req_param.qp_type                    = IBV_QPT_RC;
    req_param.qp_num                     = _dataQpNum;
    req_param.starting_psn               = _dataQpNum;;
    req_param.service_id                 = htonll(SERVICE_ID);

    req_param.primary_path               = &path_record;
    req_param.alternate_path             = NULL;
    req_param.private_data               = NULL;
    req_param.private_data_len           = 0;

    req_param.responder_resources        = 4;
    req_param.initiator_depth            = 4;
    req_param.remote_cm_response_timeout = 20;
    req_param.local_cm_response_timeout  = 20;
    req_param.retry_count                = 7;
    req_param.rnr_retry_count            = 7;
    req_param.max_cm_retries             = 5; 

    path_record.sgid             = _localGid;
    path_record.dgid             = _remoteGid;
    path_record.slid             = htons(_localLID);
    path_record.dlid             = htons(_remoteLID);
    path_record.flow_label       = 0;
    path_record.hop_limit        = 0;
    path_record.traffic_class    = 0;
    path_record.pkey             = 0xffff;
    path_record.sl               = 0;
    path_record.rate             = IBV_RATE_10_GBPS;
    path_record.packet_life_time = 0;
    path_record.mtu              = IBV_MTU_2048;