SAS issues that need quick resolution

George Penokie gop at us.ibm.com
Wed Jan 8 12:09:20 PST 2003


* From the T10 Reflector (t10 at t10.org), posted by:
* George Penokie <gop at us.ibm.com>
*




A few SAS issues have been discovered that need to be resolved quickly as
they may impact hardware design. This is a heads up on them so you can be
ready to discuss them next week.

Issue 1 from section 7.1.4.5 CLOSE
***
There is no indication as to what a device should do if it does not support
STP and receives a CLOSE (CLEAR AFFILIATION). I suggest the description
should be changed to << Close an open STP connection and clear the
initiator affiliation. If a device does not support STP it shall process
the CLOSE (CLEAR AFFILIATION) the same as CLOSE (NORMAL). >>

This needs to be resolved to prevent interoperability problems. May be not
in real life but the testers will have a field day with this if we don't
define a specific behavior for SSP devices.

Issue 2 from section 7.12.2.2 Connection request responses
***
The requirement  << After receiving an OPEN_REJECT that indicates a retry
may be performed (see table 62), the source port shall wait a retry delay
of 15 µs before issuing another connection request to the same destination
port. >> should be removed as it only adds needless complexity to targets
and initiators. It's also not clear the reason for this requirement as the
open/reject functionally will most likely be contained totally in hardware.

Issue 3 from 9.2.1 SSP frame format
****
The statement  <<The target port shall set this field to FFFFh for all
frames other than XFER_RDY frames. >>  should be deleted.

The tag should have meaning to the target only.  The current  requirement
suggests that the initiator may expect and verify that the tag is FFFFh for
non-XFER_RDY frames. This should not happen.

Some target implementations would prefer to use target port transfer tag to
keep track of frames.  That makes it easy to associate a frame in an
analyzer trace (read data, response, etc.) with a particular command.

Bye for now,
George Penokie

Dept 2C6  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-2880


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