[alsa-devel] [PATCH 1/2] ASoC: Allow drivers to specify how many bits are significant on a DAI

Mark Brown broonie at opensource.wolfsonmicro.com
Tue Jan 17 19:59:53 CET 2012

On Tue, Jan 17, 2012 at 07:51:29PM +0100, Peter Ujfalusi wrote:

> >> Yeah, but it is not correct. If it does not know this we have 8bit
> >> 'latency' in gain control. Pulse can change the gain which will have no
> >> effect.

> > Which will have the same overall effect as if it doesn't do anything
> > based on knowing the resolution.

> But we still 'loose' 8bits. It might be not a big loss at the end when
> PA for example applies the gain, but for sure we will loose resolution
> (8bit worth).

Whereas if you do the gain to the lower resolution you'll discard the
same amount of information...

> My only problem is to say this to application: "out of 8/16bit you
> should use 24msb". AFAIK this is the meaning of the constraint. This
> constraint makes sense for 32bit samples: "out of 32bit you should use
> 24msb".

Well, like I say I don't see this as a problem and have no intention of
writing any code to handle that myself.

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