SAS - Initiator closing STP connection restriction?

Elliott, Robert (Server Storage) Elliott at hp.com
Tue Aug 27 12:37:27 PDT 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <Elliott at hp.com>
*
If the initiator originates a CLOSE, it might do so just as the target
starts sending a frame and cross that frame on the wire.  The expander
cannot back off the SATA target once it starts accepting the frame, so
is stuck buffering a frame it cannot deliver.  Plus, the SATA bus is
hung until that frame is delivered - either with HOLD (if the expander
buffered 20 dwords) or waiting for an R_RDY (if the expander buffered 8
KB or more data and accepted the full frame frame data).

Meanwhile, another initiator might try to open the target.  The expander
would have to reject new OPENs until it can get the original initiator
open again and unload the frame, or it has to maintain more and more
initiator context.

It seemed safest to require the expander control closing connections.
It can offer vendor-unique programmable levels from "close often" to
"close rarely" (standard proposals welcome).

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



> -----Original Message-----
> From: Day, Brian [mailto:bday at lsil.com] 
> Sent: Monday, August 26, 2002 2:56 PM
> To: 't10 at t10.org'
> Subject: SAS - Initiator closing STP connection restriction?
> 
> 
> * From the T10 Reflector (t10 at t10.org), posted by:
> * "Day, Brian" <bday at lsil.com>
> *
> In section 7.15.3 of SAS rev 1, it restricts the STP 
> initiator from originating the closing of an STP connection.
> 
> What is the reason for this restriction?
> 
> Brian Day
> LSI Logic
> *
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