2010/2/16 Lennart Poettering mznyfn@0pointer.de
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
Refer to http://pulseaudio.org/wiki/BadDecibel
If (when flat volumes are enabled in PulseAudio) the playback volume of one stream changes whenever another stream is played, this is most likely caused be incorrect dB attenuation data exposed by the ALSA kernel driver.
This seem to the software attenuation of the playback volume when PA software mix two or more playback streams