[alsa-devel] alsactl adds volume controls?

[Raymond Yau]

2010/10/8 Colin Guthrie <gmane at colin.guthr.ie>

> D: alsa-mixer.c: Activating path analog-output
> D: alsa-mixer.c: Path analog-output (Analog Output), direction=1,
> priority=99, probed=yes, supported=yes, has_mute=yes, has_volume=yes,
> has_dB=yes, min_volume=0, max_volume=31, min_dB=-97.5, max_dB=0
> D: alsa-mixer.c: Element Master, direction=1, switch=1, volume=1,
> enumeration=0, required=0, required_absent=0, mask=0x3600000000f66,
> n_channels=2, override_map=yes
> D: alsa-mixer.c: Element PCM, direction=1, switch=0, volume=1,
> enumeration=0, required=0, required_absent=0, mask=0x3600000000f66,
> n_channels=2, override_map=yes
> I: alsa-sink.c: Hardware volume ranges from -97.50 dB to 0.00 dB.
> I: alsa-sink.c: No particular base volume set, fixing to 0 dB
> I: alsa-sink.c: Using hardware volume control. Hardware dB scale supported.
> I: alsa-sink.c: Using hardware mute control.
>

If step 0 of the Master Volume control is SND_CTL_TLV_DB_GAIN_MUTE (i.e.
-99999dB) , step 1 is -45dB and step 31 is 0dB

does it mean that the mixer application can no longer rely on
snd_mixer_selem_get_playback_dB_range() to get the correct min dB at min
step from snd_mixer_selem_set_playback_volume_range() ?

the dB range of PCM soft is -51dB to 0dB

how do PA calculate the range -97.5dB to -dB as it is not possible to set
total dB value to -97.5dB any more ?