[alsa-devel] Bug in alsa-lib or alsamixer and amixer

Raymond Yau superquad.vortex2 at gmail.com
Wed Jun 16 00:29:36 CEST 2010

2010/6/16 Colin Guthrie <gmane at colin.guthr.ie>

> 'Twas brillig, and Raymond Yau at 15/06/10 00:43 did gyre and gimble:
> > +12dB(400%) is even larger than the software gain 150% of PA
> Software gain of PA 150% = ~+11dB, so not as different as you imply.
> I've explained the cubic mapping already, so please don't use arbitrary,
> differently calculated percentages when comparing things. It's like
> comparing apples to oranges.
> Col
When I changed the volume slider of the gnome sound applet ( select
perference ) in Fedora 13 to maximum (i.e. PA 150% )

Seem to be bug in amixer and alsamixer

alsamixer also change to 150% but press any key change back to 100%

The volume range is only from 0 to  65536

why did alsa-lib allow alsa-pulse plugin to set it outside the range ,
alsamixer and amixer also display 150% ?

amixer -D pulse
Simple mixer control 'Master',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 65536
  Front Left: Playback 98304 [150%] [on]
  Front Right: Playback 98304 [150%] [on]

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