#12400 NORM 13.1.0: Determine MMP3 audio buffer parameters

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Mon Mar 25 18:52:27 EDT 2013

#12400: Determine MMP3 audio buffer parameters
           Reporter:  dsd       |       Owner:  saadia       
               Type:  defect    |      Status:  new          
           Priority:  normal    |   Milestone:  13.1.0       
          Component:  kernel    |     Version:  not specified
         Resolution:            |    Keywords:               
        Next_action:  diagnose  |    Verified:  0            
Deployment_affected:            |   Blockedby:               
           Blocking:            |  

Comment(by dsd):

 Now when I try 64kb for each stream, it fails with a memory allocation
 error message. Not sure why I found otherwise earlier.

 This matches my reading of the code. The firmware offers 128kb ASRAM to
 Linux. The mmp-pcm driver claims 64kb for each channel, 128kb total. Then
 the tdma code tries to claim 256 bytes for descriptors, and fails because
 there is no memory left.

 Mitch was right, and the allocation strategy must keep this in mind.
 Reserving 1kb for buffers sounds sensible.

 So marvell,buffer-sizes should state:
  1. 62kb (playback buffer)
  2. 2048 (playback max period size)
  3. 62kb (recording buffer)
  4. 2048 (recording max period size)

 I don't know what considerations should be applied for choosing max period
 size, so I'm simply suggesting the values that are already in use in the

Ticket URL: <http://dev.laptop.org/ticket/12400#comment:9>
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