[alsa-devel] Verifying mixer dB data/Invalid dB data from USB cards, especially Aureon 5.1 MkII

[Raymond Yau]

2010/2/16 Lennart Poettering <mznyfn at 0pointer.de>

> Heya,
>
>
> Invalid dB data from the driver is a real problem for the "flat
> volume" logic in PA. We basically allow each app to control the full
> hw volume range individually, and then set the hw volume to the max of
> what all apps wanted and attenuate the other streams accordingly. On
> the Aureon this doesn't work at all, since the attenuation of the
> streams is miscalculated due to the invalid dB data.
>
> Lennart
>

The real problem for the "flat volume" logic in PA is when you set the
hardware device volume to maximum, you cannot compensate the software attent
when PA software mixing two or more audio stream by increase the gain in
DAC