Questions on proposal 08-015

Gerry.Houlder at Gerry.Houlder at
Tue Dec 2 14:36:46 PST 2008

* From the T10 Reflector (t10 at, posted by:
* Gerry.Houlder at
I have some questions on which I need advice of expander folks.
(1) 08-015r5 currently uses byte 13, bits 5 and 4, of the DISCOVER response
to report the Phy PS Condition field. It has been pointed out that is area
of the DISCOVER response is intended to line up with related fields in the
IDENTIFY address frame and should not be used for things that are not in
the IDENTIFY address frame. However we are adding capability bit(s) (there
is an outstanding question of whether we need one or two bits here) to the
IDENTIFY address frame.
(1a) If we add two bits for "capability" in the IDENTIFY address frame,
should those capability bits be reflected in the DISCOVER response?
(1b) Can we use the related two bit field for reporting Phy PS Condition
instead of the capability bits? Is there a need to report both the
capability bit field(s) in DISCOVER response as well as the actual Phy
Condition field?
(1c) Presuming I have to move the two bit Phy Condition field elsewhere, is
it important that the field also show up in the short format DISCOVER
response? Most of those fields overlap with the fields intended to overlap
with IDENTIFY address frame usage, so if this is important we may have to
break that overlap rule.
(1d) I am expecting to move the two bit Phy Condition field either to byte
34 bits 7 & 6 or byte 6 bits 7 & 6. Any preference on these?
(2) There is a need to create two bits to enable use of partial and slumber
on expander phys. The most obvious choice is the CONFIGURE GENERAL request.
Would byte 8 of CONFIGURE GENERAL be a good choice?
(3) It has been suggested that the Protocol Specific Port mode page is not
the right choice for controlling the target device. It has been suggested
that the two enable bits for slumber and partial phy power conditions
should be in the Enhanced Phy Control mode page (page 19h, subpage 3). I
think the best place is byte 19 bits 2 & 1. Any disagreement with this?
Please post opinions to me or to the reflector on these options by Dec. 12.
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