[alsa-devel] PulseAudio and SNDRV_PCM_INFO_BATCH

[Lars-Peter Clausen]

On 06/22/2015 04:35 AM, Raymond Yau wrote:
>
>  >
>  > DMA_RESIDUE_GRANULARITY_BURST means it can report the position with a
> granularity of a few samples. Typically half the audio FIFO size.
>  >
>  >
>
> How many soc driver/platform dma engine support DMA_RESIDUE_GRANULARITY_BURST ?

Not sure, maybe half of them. But most of the time it is a software 
restriction rather than a hardware restriction and more and more drivers are 
supporting it.

>
> Are all soc audio driver use cyclic dma ?

I'm not sure I understand the question. All audio drivers use some kind of 
cyclic DMA. ASoC platforms which do not have a dedicated audio DMA typically 
use dmaengine for this, while others which have dedicated audio DMA do the 
DMA as part of the audio driver.