Potential XL State Machine holes

Fred Dutton fred.dutton at qlogic.com
Wed Jan 14 16:24:23 PST 2004


* From the T10 Reflector (t10 at t10.org), posted by:
* Fred Dutton <fred.dutton at qlogic.com>
*

I am confused about some of the XL state machine transitions described in SAS 1.1 Revision 2 in section 7.15.

I noticed the specification doesn't always explain what transitions have priority when two or more events, that would result in 
different transitions, occur simultaneously. I don't know if the situations described below are possible or if they represent real 
problems.

I would appreciate it if someone could address the following concerns and/or questions:

Thank you!


Transitions out of XL1
----------------------
What is the correct transition when:

1) An Arb Won confirmation is received at the same time as a BREAK Received message
2) An Arb Reject confirmation is received at the same time as a BREAK Received message
3) An Arb Lost confirmation is received at the same time as a BREAK Received message

Should the XL1:Request_Path to XL9:Break transition have priority over all other transitions?

Transitions out of XL3
----------------------
The XL2:Request_Open to XL3:Open_Confirm_Wait transition description (7.15.5.2) states: "If a BREAK Received message is received, 
this state shall include a BREAK Received argument with the transition.". However, there is no mention of this "argument" and its 
results once the XL3 state is entered (i.e. send a Transmit Break request to the ECR). Perhaps some clarification text could be 
added to section 7.15.6.1 (similar to the description in 7.15.9.1)

Is it possible to receive a BREAK Received message at the same time as Transmit Break indication? If so, what is the correct 
transition out of XL3?

Transitions out of XL4
----------------------
The XL4:Open_Reject state is not sensitive to BREAK Received messages. Is this acceptable?

Transitions out of XL6
---------------------- 
Is it possible to receive a BREAK Received message at the same time as Transmit Break indication? If so, what is the correct 
transition out of XL6?

Transitions out of XL7
----------------------
Is it possible to receive a BREAK Received message at the same time as Transmit Break indication? If so, what is the correct 
transition out of XL7?

What is the correct transition if a BREAK Received message is received at the same time as a Transmit Close indication? Should the 
state machine transition to the XL8:Close_Wait state with a BREAK Received argument included with the transition?

Transitions out of XL8
----------------------
Is it possible to receive a BREAK Received message at the same time as Transmit Break indication? If so, what is the correct 
transition out of XL8?


Thanks for your help.

Fred Dutton

__________________________________________
Fred Dutton
QLogic Corporation
949.389.6340


__________________________________________
Fred Dutton
QLogic Corporation
949.389.6340

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