data IU exception handling

Sriram Srinivasan srirams at lsil.com
Thu Aug 17 15:24:28 PDT 2000


* From the T10 Reflector (t10 at t10.org), posted by:
* Sriram Srinivasan <srirams at lsil.com>
*
   I have a question on data IU exception handling:
   
   In 10.8.3.3.3 (SPI4-rev0) paragraph 4 it states:
   
   "If the information unit that failed was not a SPI status information unit 
and the message received from the initiator was an INITIATOR DETECTED ERROR 
message then the target <SHALL> send a SPI L_Q/SPI status information unit pair 
to the initiator with a CHECK CONDITION status and a sense key set to ABORTED 
COMMAND and ..."
   
   Paragraph 6 of 14.1 states:
   
   "The initiator shall save the data pointers as soon as the last byte of the 
last iuCRC for a SPI information unit is transferred.  The save <SHALL> occur 
even if the initiator detects an error in the SPI data information unit.  If a 
target retries an operation it <SHALL> send a MODIFY DATA POINTERS message then 
request that the SPI data information unit be transferred again."
   
   Doesn't the first one (para 4 in 10.8.3.3.3) say that tha target cannot retry 
the command ('coz he sent the ABORTED COMMAND sense key)?  In this case, the 
initiator would probably resend the whole command again.  But para. 6 of 14.1 
seems to imply that targets can retry the SPI data IU and mandates that the 
MODIFY DATA POINTES message be sent prior to such a retry.  These seem to 
contradict each other.  The same wordings are present in SPI-3 as well.

  Is there a bigger thing that I'm missing here?  Please let me know.
  
  Thanx,
  Sriram

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 Sriram Srinivasan                       Sriram.Srinivasan at lsil.com
 ASIC Design Engineer, LSI Logic,
 2001 Danfield Ct., 				Phone: 970-206-5847
 Fort Collins, CO 80525				FAX  : 970-206-5244
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