[alsa-devel] [PATCH RFC 0/2] da850 mcasp playback ping-pong buffers don't work

Ben Gardiner bengardiner at nanometrics.ca
Fri May 13 23:26:44 CEST 2011

Hi All, 

I've been testing playback on the da850evm. The good news is on 2.6.39-rc7
playback works fine. The bad news is that if the patches in the series 
are applied -- playback does not work. 

The first patch copies the sram-size platform data to the dma parameters
used by davinci-pcm the same way that the existing davinci-i2s driver 
does. The second patch assigns a buffer size to the playback sram platform
data and sets the queues as per Troy's introduction of ping-pong buffers.

I was hoping this would result in playback of audio; but instead there is 
soft click and then silence. I added pointer debug and observed that the 
period_update and hwptr_update events progress; but that's as far as I 
have probed. 

Does anyone have any clues why ping-pong buffers on da850 to the McASP 
would work? Or any clues why the patches are broken?

Best Regards,
Ben Gardiner

Ben Gardiner (2):
  [RFC] ASoC: davinci-mcasp: enable ping-pong SRAM buffers
  [RFC] da850evm: enable mcasp ping-pong buffers

 arch/arm/configs/da8xx_omapl_defconfig  |    1 +
 arch/arm/mach-davinci/board-da850-evm.c |    4 +++-
 sound/soc/davinci/davinci-mcasp.c       |    2 ++
 3 files changed, 6 insertions(+), 1 deletions(-)


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