#12751 NORM Future : XO-4 CP tag does not work first try

[Zarro Boogs per Child]

#12751: XO-4 CP tag does not work first try
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           Reporter:  Quozl                |       Owner:  Quozl               
               Type:  defect               |      Status:  new                 
           Priority:  normal               |   Milestone:  Future Release      
          Component:  ofw - open firmware  |     Version:  Development firmware
         Resolution:                       |    Keywords:                      
        Next_action:  diagnose             |    Verified:  0                   
Deployment_affected:                       |   Blockedby:                      
           Blocking:                       |  
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Old description:

> Reproducer:
>  * add-tag CP
>  * laptop restarts
>  * remove all power
>  * insert power
>
> Expected: laptop automatically turns on.
>
> Observed: no response.
>
> Workaround: restart to the ok prompt and type sync-ec?

New description:

 Reproducer:
  * add power,
  * at the ok prompt, type ''add-tag CP'' ,
  * laptop restarts,
  * remove all power,
  * insert power.

 Expected: laptop automatically turns on.

 Observed: no response.

 Workaround: delete and re-add the tag without depowering the EC, or
 restart to the ok prompt and type ''?sync-ec'' .

--

Comment(by Quozl):

 In Open Firmware, ''?sync-ec'' is coded to occur as part of ''add-tag'',
 but the evidence from the EC Flash is that sometimes it does not complete.

 The EC serial output on power up will contain "CP enabled" if the CP tag
 is properly stored in the EC Flash.  That is, if the byte in the page
 contains the letter 'C'.  If the byte is unprogrammed or programmed to
 zero, it is treated as not present.

 During an ''add-tag CP'' test that reproduces the symptom, the "CP
 enabled" message is missing.  After the workaround ''?sync-ec'' the "CP
 enabled" message is present.

 During a ''delete-tag CP'' test, it is immediately missing.

 An ''add-tag CP'' test occasionally passes with ''CP enabled'' seen.  In
 several test cycles, this was most likely if the EC had been recently
 programmed before the previous power up.

 During an ''add-tag CP'' test, stepping through ''?reflash-ec-flags'' with
 a one second delay between steps does not prevent the symptom.

 Analysis: Open Firmware is trying to program the page, but the page is not
 programmed successfully if the EC has not been previously programmed since
 power up.  However, the experience with ''delete-tag'' suggests the page
 erase does succeed even if the page programming does not.

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Ticket URL: <http://dev.laptop.org/ticket/12751#comment:1>
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