[alsa-devel] [RFC] Initialize volumes of HD-audio slave ctls

Takashi Iwai tiwai at suse.de
Fri Mar 9 07:43:27 CET 2012

At Fri, 9 Mar 2012 07:04:23 +0800,
Raymond Yau wrote:
> 2012/3/8, Takashi Iwai <tiwai at suse.de>:
> > Hi,
> >
> > the patch below is an attempt to initialize the volume / mutes of
> > slave controls (such as "Headphone", "Speaker") with vmaster in
> > HD-audio, so that the sound can come out only by changing the master
> > volume/mute.
> >
> > We have thought that such initializations could be done well in
> > alsactl init, but it seems that not everyone installs the latest and
> > greatest alsactl, and there is always a risk that any new controls may
> > be added before alsactl is updated and released.  Since the master
> > volume is set muted, the risk by this change should be low.
> >
> > patch_cirrus.c still doesn't support this because it's handling
> > vmaster by itself, but it can be fixed later, too.
> >
> > If anyone has a concern by this, please let me know.
> >
> Can you explain the dB calculation of the volume controls when there
> is a "virtual master" ?
> The Documentation only mention that all the slaves must have the same dB range

Well, more exactly, it'd work if the volume step is the same and the
volume range of the first slave covers the all range.


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