#12289 HIGH 4-softw: XO-4 frequently records silence at non-48k rates

Zarro Boogs per Child bugtracker at laptop.org
Thu Feb 28 09:59:00 EST 2013

#12289: XO-4 frequently records silence at non-48k rates
           Reporter:  cjb        |       Owner:  saadia       
               Type:  defect     |      Status:  new          
           Priority:  high       |   Milestone:  4-software   
          Component:  kernel     |     Version:  not specified
         Resolution:             |    Keywords:  audio        
        Next_action:  never set  |    Verified:  0            
Deployment_affected:             |   Blockedby:               
           Blocking:             |  
Changes (by dsd):

 * cc: rsmith (added)


 A session on the scope yesterday verified that the codec is sending all-
 zero data when the failure is hit (thanks Richard).

 Our next suspicion is some kind of i2c communication failure when setting
 up the codec for recording. We'll try to track this with the scope.

 When starting recording at 32k, the data written to the i2c bus is:
 34 80 00
 3a 80 80
 3b 00 08
 3b 08 28
 3a 8c 80

 And when stopping:
 3a 80 80
 3b 00 08
 3a 00 00
 3b 00 00

 I can't see any variance in this communication from the linux side, and
 there aren't any obvious i2c write errors.

Ticket URL: <http://dev.laptop.org/ticket/12289#comment:7>
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