[alsa-devel] [PATCH 0/4] McBSP smart idle and DMA op mode updates for ASoC

[Jarkko Nikula]

On Tue, 18 May 2010 21:13:10 +0100
Liam Girdwood <lrg at slimlogic.co.uk> wrote:

> I've also added a patch to remove the mcbsp DMA op mode sysfs set functionality.
> I think DMA op mode is very specific to the mcbsp client driver _only_ and
> shouldn't really be changed by userspace. Please let me know if you use this
> feature and I'll drop this patch.
> 
I've used to say that the DMA op mode is more like use-case not machine
specific but I'm not sure is my point valid onemore. I've used to think
that low-latency processing would need accurate DMA pointer (op
mode == element) while mp3 playback would need low power consumption
(op mode == threshold).

Peter: what's the status today how well can we do low-latency
processing with threshold mode? IRCC, with your FIFO delay query
patches, can we estimate the DMA pointer position with enough accuracy?


-- 
Jarkko