#12400 NORM 13.1.0: Determine MMP3 audio buffer parameters

Zarro Boogs per Child bugtracker at laptop.org
Fri Jan 11 12:32:30 EST 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 wmb at firmworks.com):

 You can't use all of the SRAM for buffers because you need some for ADMA

 Maybe qseven works with 64k because no SRAM is earmarked for CForth, thus
 it still has room for descriptors.

 The test version of OFW that I gave saadia reports 31K for each buffer,
 leaving a total of 0x1000 bytes for descriptors.  I used 31K instead of
 62K because I wasn't sure whether Linux was assuming double-buffering and
 thus allocating 4 buffers (2 playback, 2 capture).  I now suspect that 62K
 for each buffer might be better, under the assumption that the total
 buffer space is carved into more than two buffers per direction.

Ticket URL: <http://dev.laptop.org/ticket/12400#comment:8>
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