Packetized L_Q IU type field changes

Gerry_Houlder at notes.seagate.com Gerry_Houlder at notes.seagate.com
Wed Dec 15 08:56:41 PST 1999


* From the T10 Reflector (t10 at t10.org), posted by:
* Gerry_Houlder at notes.seagate.com
*
Maybe I am missing something, but the target doesn't have to break the 'multiple
command' stream with a QUEUE FULL status. Can't it just accept one multiple
command SPI L_Q, accept the command packet, then disconnect if it doesn't want
to take any more commands? The more difficult case occurs with even a 'last
command' SPI L_Q when the target can't accept even one command, therefore it
must return QUEUE FULL status.

I agree that if the initiator can tolerate a sequence of:
(a) outbound SPI L_Q with command type,
(b) inbound SPI L_Q with status type,
(c) inbound status packet with QUEUE FULL status;

then a sequence where the inbound status packet is CHECK CONDITION (because the
target sees an illegal SPI L_Q packet) should also be allowed.





"Bill Galloway" <BillG at breatech.com> on 12/15/99 10:15:36 AM

Please respond to BillG at breatech.com

To:   Mark Heath at Seagate, gop at us.ibm.com
cc:   t10 at t10.org (bcc: Gerry Houlder)

Subject:  RE: Packetized L_Q IU type field changes



* From the T10 Reflector (t10 at t10.org), posted by:
* "Bill Galloway" <BillG at breatech.com>
*
Mark,

The Note that George pointed out does allow the target to break a "multiple
command" sequence with status. It just cannot break it for any other reason.  I
can imagine other reasons that a target may want to break the stream. It may
have a buffer congestion problem and needs time to get previous commands out of
the protocol chip (no the same as queue full). It may have data already staged
for a command and really needs to send the data NOW. If the initiator has to
handle the broken stream case for status it would seem that it could handle it
at other times as well.


Bill Galloway
BREA Technologies, Inc.
P: (281) 530-3063
F: (281) 988-0358
BillG at breatech.com



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