iSCSI: SCSI Event Indicator

["Elliott, Robert" <Robert.Elliott@compaq.com>]

The Asynchronous Event data structure includes an "iSCSI Event
Indicator" field and a "SCSI Event Indicator" field.  The iSCSI
field indicates iSCSI-specific causes, which is fine.  The SCSI 
Event field indicates generic SCSI causes.  

I suggest removing the SCSI Event Indicator values.  The 
information is contained within the sense data itself.

The SEND command in SPC-2, the current mechanism to report 
Asynchronous Events, does not include an Event field like this.

I suggest simplifying the field to:
    0 = not a SCSI Event
    1 = SCSI Event

This is the text in iSCSI revision 02, with comments
listing where in the sense data that information is
communicated:

   2.17.2 SCSI Event Indicator 
 
   The following values are defined.  (See [SAM2] for details): 
    
      1    An error condition was encountered after command 
      completion. 
[Sense data RESPONSE CODE field is DEFERRED ERRORS - 71h]

      2    A newly initialized device is available to this initiator. 
[Sense data ASC/ASCQ is REPORTED LUNS DATA HAS CHANGED]

      3    All Task Sets are being Reset by another Initiator 
[Sense data ASC/ASCQ is COMMANDS CLEARED BY ANOTHER INITIATOR]

[where is 4?]

      5    Some other type of unit attention condition has occurred. 
[Sense data SENSE KEY field is UNIT ATTENTION - 6h]

      6    An asynchronous event has occurred. 
[Any other sense data]

   Sense Data accompanying the report identifies the condition.  The 
   Length parameter is set to the length of the Sense Data. 
    
   For new device identification an iSCSI target MUST support the Device 
   Identification page. 


The list was probably taken from this list in SAM-2; however, it's
not an exact match:

    Asynchronous Event Reporting is used to signal a device that 
    one of the four events listed below has occurred:
    a) an error condition was encountered after command completion;
    b) a newly initialized device is available;
    c) some other type of unit attention condition has occurred; or
    d) an asynchronous event has occurred.

---
PC: Robert.Elliott@compaq.com
UNIX: relliott@unixmail.compaq.com