#1735 BLOC Trial-2: Audio clicking on resume.

[Zarro Boogs per Child]

#1735: Audio clicking on resume.
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  Reporter:  jg       |       Owner:  dilinger    
      Type:  defect   |      Status:  new         
  Priority:  blocker  |   Milestone:  Trial-2     
 Component:  kernel   |     Version:  Build 406.14
Resolution:           |    Keywords:  power       
  Verified:  0        |  
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Comment (by jayakumar):

 Replying to [comment:15 jg]:
 > whether the microphone power being on when it shouldn't is related to
 the clicking is unclear.

 Yes, you are correct. There is no direct dependency between the two.
 Basically, the AC97 power saving method is to fully turn off the codec
 whenever the device is idle for x seconds, and then turn it back on when
 any process accesses audio. That means that that the mic LED which is tied
 to VRef also goes on and off each time that happens, as does the pop/click
 that you hear which is coming from ac97 resume.
 I recognize 2 bugs here. 1 is the pop/click on resume which is a bug in
 our ac97 resume code. 2 is that we currently default to V_Ref bias being
 enabled whereas on OLPC it ought to default to being off until we detect a
 jack insertion.

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Ticket URL: <http://dev.laptop.org/ticket/1735#comment:18>
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