[alsa-devel] CMI8788/AV200/Oxygen Volume Controls in alsamixer (oxygen_mixer.c:dac_volume_get())

[Takashi Iwai]

At Fri, 23 Jan 2009 11:08:23 -0800,
John Utz wrote:
> 
> using exchange webmail today, sorry.
> 
> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai at suse.de]
> Sent: Fri 1/23/2009 5:56 AM
> To: Clemens Ladisch
> Cc: John Utz; ALSA Developers
> Subject: Re: [alsa-devel] CMI8788/AV200/Oxygen Volume Controls in alsamixer
> (oxygen_mixer.c:dac_volume_get())
> 
> At Fri, 23 Jan 2009 14:51:31 +0100,
> Clemens Ladisch wrote:
> >
> > John L. Utz III wrote:
> > > It appears to me that these functions are attempting to work on all of
> > > the channels at once instead of just choosing Master, Front, Rear,
> > > Surround, or what have you:
> >
> > Yes, the "Master" control is one control with eight channels.
> >
> > > this leads to a rather awkward result in alsamixer where there are 5
> > > volume controls called "Master":
> > >
> > > < Master >  Master    Master    Master    Master
> > >
> > > IMHO, it would be more desirable for them to say:
> > >
> > > < Master >  Front     C/LFE     Surround  Rear Surr
> >
> > Yes.
> >
> > Alsamixer chooses to display an eight-channel control this way.  This
> > can be considered a bug in alsamixer.
> 
> The current ALSA mixer abstraction splits the multi-channels into
> separate paired channels.  But alsamixer can't show the channel name
> due to its UI design.  And I guess other mixer apps don't handle them
> properly, too (who would care?).
> 
> A solution would be make individual control like "Front", and create a
> virtual master control.
> 
> JU a virtual control in the conf file or in the driver?

In the driver.  See sound/core/vmaster.c.


Takashi