[alsa-devel] DMA and delay feedback

pl bossart bossart.nospam at gmail.com
Mon Dec 14 15:46:27 CET 2009

> For transfer purposes, one only needs to know that DMA transfer is
> complete on period X so that period X can now be over-written.

That's the 'traditional' view. ALSA is now used in different ways.
PulseAudio sets a timer and relies on snd_pcm_avail() to query how
many samples it can write to the ring buffer, the notion of period
isn't used at all. I think we could use additional information in the
way the hw_ptr position is reported, namely hints on how precise this
information is and the granularity of the updates.
- Pierre

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