Re: [alsa-devel] [RFC][PATCH] ASoC: add simple-graph-card document

On Tue, Jan 24, 2017 at 03:10:48PM +0100, Sylwester Nawrocki wrote:

Is the main difference between "normal" and DPCM card that in case of the
former the data flow routes are static and the latter allows dynamic
reconfiguration of sound data routes? AFAIU DPCM stands here for Dynamic
PCM [1], rather than Differential Pulse Code Modulation.

DPCM is a Linux internal abstraction that doesn't represent what's going
on in a very generic fashion which makes it problematic when it appears
directly in DT bindings.  It's very SoC centric.

It seems the graph based binding could cover above both cases.  Apologies
if this has been explained before, but what are main reasons for introducing
the graph based binding?

The simple card is creaking at the seams as it was only really designed
to represent very simple use cases but has been extended rather beyond
that.  It's also not set up to cope with things like CODEC<->CODEC links
that don't involve the CPU as it really only has the idea of point to
point links between a CPU DAI and a CODEC DAI.

Is the SCU part in "ASoC simple SCU Sound Card" derived from "(S)ample Rate
(C)onverter (U)nit" ?

Yes.