SPC-3 MRIE=async and Control mode page UAAERP bit

Elliott, Robert (Server Storage) Elliott at hp.com
Tue Jun 25 19:18:08 PDT 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <Elliott at hp.com>
*
In SPC-3, the Informational Exceptions Control mode page contains a Method for Reporting Informational Exceptions (MRIE) field which controls how informational exceptions are reported.  The 1h value indicates that asynchronous event reporting shall be used.

However, the Control mode page contains a Unit Attention Asynchronous Event Reporting Permission (UAAERP) bit that controls whether unit attentions are allowed to generate asynchronous event reports.

I think the UAAERP bit overrides the MRIE value; if UAAERP is 0, the asynchronous event reports from the MRIE setting won't get through.  Software must set UAAERP to 1 if it wants to use a MRIE value of 1h.

I suggest adding the text in [] to mention this in the MRIE table:

8.4.10 Informational Exceptions Control mode page
...
The method of reporting informational exceptions field (MRIE) indicates the methods that shall be used by the device server to report informational exception conditions (see table 234). The priority of reporting multiple information exceptions is vendor specific.

Method of reporting informational exceptions (MRIE) field (part 1 of 2)
...
1h: Asynchronous event reporting: This method instructs the device server to report informational exception conditions by using the rules for asynchronous event reporting as described in SAM-2 and the relevant SCSI protocol standard. [The informational exception conditions are not reported if the UAAERP bit is set to zero in the Control mode page (see x.x).]

The sense key shall be set to RECOVERED ERROR and the additional sense code shall indicate the cause of the informational exception condition.

...
8.4.6 Control mode page
...
The RAERP, UAAERP, and EAERP bits enable specific events to be
reported via the asynchronous event reporting protocol. When 
all three bits are zero, the target shall not use asynchronous
event reporting. AER is defined in SAM-2.
...


---
Rob Elliott, Hewlett-Packard Industry Standard Server Storage
elliott at hp.com


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