SAS SP (phy layer) state machine

George Penokie gop at us.ibm.com
Wed Apr 2 13:34:34 PST 2003


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




Jim,

The wording:

Each time this state receives a DWS Lost message, this state may send a
Start DWS message to the SP_DWS state machine if it wants to attempt to
re-acquire dword synchronization without running a new link reset sequence.

Is not very good standardize. How about:

Each time this state receives a DWS Lost message, this state may send a
Start DWS message to the SP_DWS state machine to re-acquire dword
synchronization without running a new link reset sequence.

And for the wording:

This transition shall occur after receiving a DWS Lost message, if this
state does not send a Start DWS message in response.

How about:

This transition shall occur after receiving a DWS Lost message, if this
state does not send a Start DWS message.

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




                                                                                                                                       
                      Jim.Coomes at seagat                                                                                                
                      e.com                    To:       T10 Reflector <t10 at t10.org>                                                   
                      Sent by:                 cc:                                                                                     
                      owner-t10 at t10.org        Subject:  SAS SP (phy layer) state machine                                              
                                                                                                                                       
                                                                                                                                       
                      03/31/2003 03:21                                                                                                 
                      PM                                                                                                               
                                                                                                                                       
                                                                                                                                       




* From the T10 Reflector (t10 at t10.org), posted by:
* Jim.Coomes at seagate.com
*
A problem was introduced to speed negotiation when sas-r03e incorporated
use of the DWS function into the SP (phy layer) state machine SAS speed
negotiation states.

The following transitions:

6.7.4.3.2 Transition SP10:SAS_AwaitALIGN to SP0:OOB_COMINIT

6.7.4.4.2 Transition SP11:SAS_AwaitALIGN1 to SP0:OOB_COMINIT

6.7.4.5.2 Transition SP12:SAS_AwaitSNW to SP0:OOB_COMINIT

6.7.4.6.2 Transition SP13:SAS_Pass to SP0:OOB_COMINIT

are taken when:

This transition shall occur after receiving a DWS Lost message.

The DWS Lost condition may occur normally during speed negotiation. As the
attached phy's transmitter goes to idle (turns off) the local receiver may
detect invalid words and result in the DWS state machine generating DWS
Lost to the SP state machine. The wording above requires a restart of Link
Reset. This could prevent successful completion of speed negotiation.

The following change is proposed after discussion with Rob:

The following wording from the SP15: SAS_PHY_Ready state should be included
in SP10, SP11, SP12 and SP13 states:

Each time this state receives a DWS Lost message, this state may send a
Start DWS message to the
SP_DWS state machine if it wants to attempt to re-acquire dword
synchronization without running a new link
reset sequence.

The above transitions should be made:

This transition shall occur after receiving a DWS Lost message, if this
state does not send a Start DWS message in response.


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