SAS SP state machine Hot-Plug Timeout timer text

[Elliott, Robert (Server Storage)]

* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <Elliott at hp.com>
*
4.4.2 "Hard reset" doesn't say anything about targets.

6.6.5 "Phy reset sequence..." says targets "should not" rather than
"shall not" implement the Hot-Plug Timeout.

I hope that disk drives won't re-run OOB more per trigger to so, but
we're not prohibiting it altogether.  Triggers to do so include power on
and loss of dword sync for no shorter than 1 ms.

The proposed change just adds "if implemented" to the state machine so
it's not interpreted as a "shall rerun OOB" for all types of phys (which
would disagree with 6.6.5).

--
Rob Elliott, elliott at hp.com
Hewlett-Packard Industry Standard Server Storage Advanced Technology
https://ecardfile.com/id/RobElliott




> -----Original Message-----
> From: Jim.Coomes at seagate.com [mailto:Jim.Coomes at seagate.com] 
> Sent: Friday, May 02, 2003 1:20 PM
> To: Elliott, Robert (Server Storage)
> Cc: t10 at t10.org
> Subject: SAS SP state machine Hot-Plug Timeout timer text
> 
> 
> Rob,
> 
> This change makes SAS confusing from a target's perspective. 
> 4.4.2 says targets should not initiate phy reset after the 
> initial time following power up. Most of the places in the 
> draft are generic about initiating phy reset such as on loss 
> of sync for 1 msec. We have interpreted 4.4.2 to mean that 
> targets do not initiate phy reset in these generic cases.
> 
> The WG in the past concluded from 4.4.2 that targets did not 
> support Hot-Plug Timeout. If this change is adopted, each 
> place in the draft where phy reset is initiated needs to be 
> reviewed to determine if it is appropriate foe targets and 
> the should not removed from 4.4.2.
> 
> Jim
> 
> 
> ----- Forwarded by Jim Coomes/Seagate on 05/02/2003 01:05 PM -----
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>                       "Elliott, Robert                        
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>                       (Server Storage)"        To:       
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>                       <Elliott at hp.com>         cc:            
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>                       Sent by:                 Subject:  SAS 
> SP state machine Hot-Plug Timeout timer text                  
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> * From the T10 Reflector (t10 at t10.org), posted by:
> * "Elliott, Robert (Server Storage)" <Elliott at hp.com>
> *
> Although the Hot-Plug Timeout timer is mandatory only for 
> expander phys (it is optional for initiator and target phys), 
> some of the wording in the SP state machine in sas-r03g makes 
> it appear to be mandatory.
> 
> (this is the "re-run OOB every 500 ms if there is no response" timer)
> 
> Proposed change:
> In both:
> 6.7.3.2 SP1:OOB_AwaitCOMX state
> 6.7.3.2.1 State description
> and:
> 6.7.3.3 SP2:OOB_NoCOMSASTimeout state
> 6.7.3.3.1 State description
> 
> Change:
> Upon entry into this state, the Hot-Plug Timeout timer shall 
> be initialized and started.
> 
> to:
> Upon entry into this state, the Hot-Plug Timeout timer shall 
> be initialized and started if this phy is:
> a) an expander phy; or
> b) an initiator phy or target phy implementing the Hot-Plug 
> Timeout timer.
> 
> 
> --
> Rob Elliott, elliott at hp.com
> Hewlett-Packard Industry Standard Server Storage Advanced 
> Technology https://ecardfile.com/id/RobElliott
> 
> 
> 
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