20.1.7 Discover a SCSI channel

It is recommended that the SCSI host controller driver construct a private context structure for each enumerated SCSI channel. See Chapter 8 in this guide for the advantage of using such a private context structure.
Specifically, the SCSI host controller driver should store all required information for the child SCSI channel in this data structure, this should including the signature, child handle value (optional for single channel controller), channel number, and any produced protocols. This private context structure can be accessed via the Record macro CR(), which is described in Chapter 8 of this document.
The method for determining the number of channels on a given controller is chip specific and varies by manufacturer. It is also the SCSI driver's responsibility to do the following:
  • Build the appropriate device path for the enumerated SCSI channel.
  • Install Extended SCSI Pass Thru Protocol and Device Path Protocol on the
    appropriate handle (child handle is optional for single channel).