NPA_HACB_Passthru provides NLM applications the ability to communicate directly with an adapter. This provides a vendor with a communications channel to allow for vendor-specific commands/data to be sent to/from the adapter. HAMs must be able to handle all messages sent to it using this API, although the HAM might return an unsupported function error if necessary. It is important to understand that if a request is sent down that causes an error and/or queue freeze, the NLM application must clear up the problem and unfreeze the queue if necessary so that the HAM can process commands normally. See the NPA_HACB_Passthru API for more details.