#8526 HIGH 8.2.0 (: display backlight dims for no good reason

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#8526: display backlight dims for no good reason
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   Reporter:  thomaswamm           |       Owner:  cjb                              
       Type:  defect               |      Status:  new                              
   Priority:  high                 |   Milestone:  8.2.0 (was Update.2)             
  Component:  power manager (OHM)  |     Version:  Development build as of this date
 Resolution:                       |    Keywords:  cjbfor8.2                        
Next_action:  diagnose             |    Verified:  0                                
  Blockedby:                       |    Blocking:  8006                             
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Comment(by thomaswamm):

 This bug has interesting variations.  Tonight a couple times I saw it
 automagically BRIGHTEN the backlight from Level3 to Level7.  I will name
 this the PowerWaster variation.

 I verified reproducibility after a Restart (same as Shutdown/power-up).

 I have seen the bug happen in multiple environments, e.g. Home view, in
 Browse, in Firefox, in Measure, and in Ruler. So it is a low-level
 infrastructure thing.

 The brightness change seems to happen always about 55 seconds after start
 of hands-off inactivity.

 The critical TimeT for the Waiting Method test case is around 60 seconds,
 plus or minus a few seconds.  Maybe critical TimeT is 55 seconds?  It is
 not easy to determine empirically.

 I have observed backlight brightness changes synchronizing to keystrokes,
 but have not done any experiments to figure it out.

 I am now going to leave this bug alone for a while, hoping the wizards now
 have enough info to devise counterspells.  By the way, there might be more
 than one bug at work.

 If a fix doesn't go into the next official signed release, just spread the
 word to avoid backlight Level8 (MAX) if the backlight changes annoyingly
 by itself.  I use Level7.

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Ticket URL: <http://dev.laptop.org/ticket/8526#comment:10>
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