[alsa-devel] wrong decibel data?
superquad.vortex2 at gmail.com
Fri Apr 9 03:35:45 CEST 2010
2010/4/8 Nicolo' Chieffo <nicolo.chieffo at gmail.com>
> I'm sorry but I found out that I gave you wrong values of "amixer -D
> pulse": I just discovered that when I lower the alsa master volume, in
> some occasions the PCM volume goes to 99%, so now I will put it to
> 100% and check the pulse volume again.
> 0 dB = 65536 [100%]
> -3 dB = 57520 [88%]
> -6 dB = 52057 [79%]
> -12 dB = 41034 [63%]
> -24 dB = 26090 [40%]
> -48 dB = 10151 [15%]
> So again, the only problem is that -48 dB IS mute, but it's not
> declared as mute.
> This is the real issue.
For AC97 codec , both Master and PCM are hardware volume controls
Register 02 - control the stereo master volume
Register 18 - PCM out volume
But on HDA , PCM is most likely a software volume control just like
pulseaudio volume control
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