#12101 BLOC 4-softw: cl4: touchpad missing after reboot

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#12101: cl4: touchpad missing after reboot
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           Reporter:  pgf        |       Owner:                                    
               Type:  defect     |      Status:  new                               
           Priority:  blocker    |   Milestone:  4-software                        
          Component:  kernel     |     Version:  Development source as of this date
         Resolution:             |    Keywords:  XO-4, touchpad                    
        Next_action:  reproduce  |    Verified:  0                                 
Deployment_affected:             |   Blockedby:                                    
           Blocking:             |  
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Comment(by dsd):

 My understanding of the clock line was incorrect. The device will only
 generate a clock signal when there is data to be sent in either direction.
 Anyway, we tried increasing the delay to 220uS, but this didn't help.

 Using sdkit to examine the GPIOs when the situation occurs:
 {{{
 ok d# 160 gpio-out? .
 ffffffff
 ok d# 107 gpio-out? .
 ffffffff
 }}}

 This means that GPIO 160 (the clock line) is an output, which means that
 it has been driven low. This is the opposite of what we would expect - it
 should have been set as an input, waiting for a clock pulse.

 Flipping it to an input causes the mouse to start working again (albeit in
 confused fashion).

-- 
Ticket URL: <http://dev.laptop.org/ticket/12101#comment:20>
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