At Tue, 12 Feb 2008 19:24:35 +0100,
Matej Laitl wrote:
quoted text
> 
> > > So there are now 3 vol controls that affect both speakers and headphones:
> > > * Master (which appeared somewhere between 2.6.24 and .25-rc1), when set
> > > to zero, the sound is still audible in speakers and headphones
> >
> > This must be the behavior of the codec chip...  Did "Front" volume 0
> > mute in the earlier version?  If not, it actually doesn't mute with
> > the lowest volume.  Use the master switch to mute.
> >
> > Anyway, attach the alsa-info.sh output at the moment Master volume is
> > zero.
> 
> No, setting Master and/or Front channel to 0% did not mute audio in any 
> version I used.
> 
> I'm now listening to music with Master=0% and Front=0%, the sound is at well 
> audible volume. Pastebin for this configuraion is here:
> http://pastebin.ca/901459

Thanks.  The amp values in the codec are indeed set to zero, so this
is the minimal volume level, but the codec chip apparently doesn't
mute the sound.

quoted text
> However I don't consider it a problem, it's mutable by PCM and HP/Speaker 
> switches. Funny thing is that resulting volume of those 3 setting is equal:
> * Master=0, Front=0
> * Master=100%, Front=0
> * Master=0, Front=100%
> But when both set to let's say 50, changing one of these audibly affects 
> resulting volume.

It's because the master volume is implemented virtually to bind
several mixer volumes together.  The codec chip has no corresponding
functionality.


Takashi
--
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/