[alsa-devel] [PATCH v2] ASoC: rt5677: make volume TLV closer to reality

[Dylan Reid]

On Thu, Oct 9, 2014 at 4:10 PM, Mark Brown <broonie at kernel.org> wrote:
> On Thu, Oct 09, 2014 at 03:11:27PM -0700, Dylan Reid wrote:
>> The volume blocks have an step of 0.375dB, but TLV uses 0.01dB for
>> units.  Switch to use TLV_DB_MINMAX as this allows the minimum to be
>> off by only 0.005dB.  This is an improvement from the ~500dB is was
>> misreported by before.
>
> The usual thing to do with these is just to halve the resolution of the
> control by ignoring the low bit so that you get exact values, though for
> this device that does result in a relatively large step (step sizes like
> 0.125dB are more common).  I dunno, doesn't make much difference either
> way from my point of view.

I can easily add a flag to the UCM config to hint userspace to divide by 10, so
I'm not strongly tied to making this change if it isn't bothering anyone else.