[alsa-devel] TLV question - ranges not in volume order
david.henningsson at canonical.com
Wed May 8 15:33:11 CEST 2013
On 05/08/2013 02:14 PM, Takashi Iwai wrote:
> At Wed, 08 May 2013 14:09:31 +0200,
> Clemens Ladisch wrote:
>> David Henningsson wrote:
>>> I recently came across a strange ASoC volume control. In this case,
>>> the values are not in volume order, i e, the control is declared
>>> something like below.
>>> However alsamixer seems not to handle this "reordering" correctly. My
>>> question is if this is something that should be fixed in alsamixer (or
>>> possibly alsa-lib?), or does one need to write some kind of mapping
>>> table in the kernel, just to make something come in volume order to
>> Items in a DB_RANGE container must be ordered by their values *and* by
>> their dB values. This implies that larger values must correspond with
>> larger dB values, whis is also required for all other mixer controls.
>> If the register values are unordered, the driver must reorder them.
> Yep. Although there is no explicit definition, it's an implicit rule,
> as we have never implemented the parser code to allow the disorder.
> We should add a text mentioning that somewhere. A patch is welcome ;)
Like this? (Feel free to apply if you think it's good)
David Henningsson, Canonical Ltd.
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