#12077 LOW 13.1.0: XO-1 lid sensor incorrectly reads as closed after Linux reboot

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#12077: XO-1 lid sensor incorrectly reads as closed after Linux reboot
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           Reporter:  Quozl                |       Owner:  Quozl 
               Type:  defect               |      Status:  new   
           Priority:  low                  |   Milestone:  13.1.0
          Component:  ofw - open firmware  |     Version:        
         Resolution:                       |    Keywords:        
        Next_action:  package              |    Verified:  0     
Deployment_affected:                       |   Blockedby:        
           Blocking:                       |  
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Changes (by Quozl):

 * cc: rsmith (removed)
  * next_action:  diagnose => package
  * component:  embedded controller => ofw - open firmware


Comment:

 Thanks.  The code you pointed me to was critical to my understanding;
 there's a GPIO pin invert register bit that is cleared on power up reset,
 but not cleared on reboot.  The reference to #5703 was also very useful.

 Changing the pin invert bit costs two cycles of a 32kHz clock for the data
 to be updated, per http://wiki.laptop.org/images/4/46/GPIO.png .  By
 XORing against the invert input bit, the true sense of the pin is obtained
 without the delay cost.  Fixed in
 [http://tracker.coreboot.org/trac/openfirmware/changeset/3278 svn 3278],
 and will be in next XO-1 Open Firmware release.

 A development build is available at
 http://dev.laptop.org/~quozl/q2f13je.rom ... which lacks svn 3235 to avoid
 a build problem.

-- 
Ticket URL: <http://dev.laptop.org/ticket/12077#comment:2>
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