Openmoko Bug #1986: AUX LED blicks too early at power on

Openmoko Public Trac bugs at docs.openmoko.org
Mon Mar 2 16:42:52 CET 2009


#1986: AUX LED blicks too early at power on
--------------------------------+-------------------------------------------
    Reporter:  h.koenig         |        Owner:  andy   
        Type:  defect           |       Status:  closed 
    Priority:  normal           |    Milestone:         
   Component:  System Software  |      Version:         
    Severity:  normal           |   Resolution:  wontfix
    Keywords:                   |     Haspatch:  0      
   Blockedby:                   |    Estimated:         
 Patchreview:                   |     Blocking:         
Reproducible:                   |  
--------------------------------+-------------------------------------------
Changes (by andy):

  * status:  assigned => closed
  * resolution:  => wontfix


Comment:

 This whole bug is just a result of broken GTA02 (mainly A5, but to a
 lesser extent on A6 too) power circuit in hardware.

 The only reason you get different behaviour depending on how long you hold
 the power button is because of insufficient VB_SYS capacitor to allow the
 device to start up properly.

 While you hold the button, the failures to boot are hidden by "automatic
 retries" via the pcf50633 state machine.  When you let go of the button
 "early", the miserable truth is revealed.  But the pcf50633 button is in
 fact edge triggered action by design, with some debounce time.

 To compound the perversity of this bug, on GTA02 A5 there is a problem
 with the amount of current the AUX LED driver draws, such that merely
 trying to light the AUX LED at all can itself directly cause the failure
 to boot and another hidden cycle of boot retry.  So what you think of as a
 safety indicator is the smoking gun already.

 So I doubt we really fix this as reported: closing as WONTFIX.

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/1986#comment:4>
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