[alsa-devel] ASoC davinci: playing mono sound doubles all samples on the i2s (pcm) bus except the first one

[Jan Pohanka]

Hello,

I'm working with a board with TI dm365 processor and using McBSP  
pheripheral to send sound samples to a GSM module. The kernel version is  
2.6.32.17 and the ASoC driver state is based on this commit  
http://arago-project.org/git/projects/?p=linux-davinci.git;a=commit;h=a4c8ea2ddaed2f461606c2828b19786524b551ac

I have configured the hw interface to send two words in a frame on 8000Hz,  
this is working fine. When playing mono waveforms I noticed that all  
samples are doubled (it should be correct because snd_pcm_hardware has  
SNDRV_PCM_INFO_INTERLEAVED flag) but except the first one, that is send  
only once. This leads to a state when one sample in each frame is delayed.  
Unfortunately I'm not an expert on ALSA and ASoC and I'm not sure whether  
this problem rises in the core of ALSA or only in the driver for davinci  
dm365 (probably somewhere in the dma handling).

Could please someone give me some hint where to find the source of the  
problem? I hope I described the situation enough...

best regards
Jan

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