#10127 BLOC 1.5-sof: DMA image corruption from camera in C3/C4

Zarro Boogs per Child bugtracker at laptop.org
Wed Apr 21 09:08:35 EDT 2010


#10127: DMA image corruption from camera in C3/C4
--------------------------------+-------------------------------------------
           Reporter:  cjb       |       Owner:  corbet             
               Type:  defect    |      Status:  new                
           Priority:  blocker   |   Milestone:  1.5-software-update
          Component:  kernel    |     Version:  not specified      
         Resolution:            |    Keywords:                     
        Next_action:  diagnose  |    Verified:  0                  
Deployment_affected:            |   Blockedby:                     
           Blocking:            |  
--------------------------------+-------------------------------------------

Comment(by corbet):

 I've had very good results by simply running an infinite loop in another
 terminal :)

 My belief is that this is a hardware problem, but that doesn't mean we're
 going to get a hardware fix.  Failing that, the right solution is as
 suggested by Deepak a while back: use the pm_qos API to keep the processor
 from dropping into C3 when DMA is active.  I've done enough digging around
 to convince myself that it will work with minimal power impact; will have
 a patch ready in the near future.

-- 
Ticket URL: <http://dev.laptop.org/ticket/10127#comment:2>
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