sys/dev/mpr/mpr_sas_lsi.c
sys/dev/mps/mps_sas_lsi.c
      When mp[rs]sas_get_sata_identify returns
      MPI2_IOCSTATUS_SCSI_PROTOCOL_ERROR, don't bother retrying. Protocol
      errors aren't likely to be fixed by sleeping.

      Without this change, a system that generated may protocol errors due
      to signal integrity issues was taking more than an hour to boot, due
      to all the retries.