[alsa-devel] [PATCH] hda: Add logic to force HP mixer creation

Takashi Iwai tiwai at suse.de
Wed Feb 18 07:43:46 CET 2009

At Tue, 17 Feb 2009 15:06:38 -0600,
Mario Limonciello wrote:
> Hi Takashi:
> Takashi Iwai wrote:
>     At Tue, 17 Feb 2009 13:27:12 -0600,
>     Mario Limonciello wrote:
>     Ah, OK, then the mic jack is connected to the surround DAC.
>     But don't you have Center and LFE?
> There aren't mixers for Center or LFE at all.  Again going back to my feelings
> about mixer names, for the purposes of a laptop I think providing a knob
> called Center or another called LFE just adds to the confusion.

Right.  Though, "Front", "Surround", "Center" and "LFE" are basically
for logical channels, not the physical I/O volumes.  So, their
meanings don't conflict conceptually.  However, in the case of laptop,
the mapping between the channel and the phyiscal I/O is unclear, which
causes confusion.

>     And any control of speaker volume?
> Speaker volume is handled by the combination of Master, PCM, and Front
> mixers.  The headphone mixer has no bearing on the volume of the speakers.

OK, that's a good news at least.

>     And exactly this is another point why I feel the necessity of
>     cleanup.  If the feature isn't needed, we should get rid of it.  Or,
>     implement in a better form.
> If I was to put a vote towards this, I think attempting to support 6 channel
> analog in the mobile space is a feature that needs to go.  It causes confusion
> and complicates the code. 


>     One more another problem is that this setup thingy isn't described
>     at all, or pretty hard to guess from the mixer control.  There are
>     knobs, but you don't know the combination.
> I think knobs, switches, do-hickeys, etc are great to have when they serve an
> explicit purpose.  I look at the mixers being presented to me, and I've no
> idea what
> "Mono Mux" is there for, or why I've got several "Digital Input Source"
> areas. 

This is another area that must be cleaned up, yes.

>     This must be included.  Check commit
>     8bb0ac5573ff0879fef511e1a80a4a4db0316daa
>     in sound git tree.
> I suppose i've got some confusion for when these commits are showing up on 
> http://git.alsa-project.org/?p=alsa-kernel.git;a=history;f=sound/pci/hda/
> patch_sigmatel.c;h=3c84817ccd2e0d4bd1eee4f2882047ae84165e10;hb=HEAD
> My understanding was that the tree alsa-kernel tree was merged into the
> alsa-driver and alsa-kmirror trees on a regular basis.  I have been operating
> off of web snapshots of alsa-driver from http://www.alsa-project.org/snapshot/
> since I can't do GIT internally here, but I'm not seeing the patch show up in
> alsa-driver there.

The tree I'm maintaining, sound git tree, is not on alsa-project.org.
It's found on kernel.org, 


and the snapshot tarball is 


The above tree is used as a reference tree to the linux-next.

Some other information is found in
$LINUX/Documentation/sound/alsa/HD-Audio.txt in the recent kernel tree.



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