[alsa-devel] 5.1 surround on 3 jacks (retasking)

[Takashi Iwai]

At Tue, 31 Aug 2010 07:45:09 +1200,
Keith Chew wrote:
> 
> Hi Takashi
> 
> > This is nothing but the raw 32 bit values the codec chip will take.
> > Refer to "default pin configuration" in HD-audio specification.
> > Definitions can be found in hda_codec.h, too (AC_DEFCFG_*).
> >
> 
> Thank you very much for this, I have managed to find it in both Intel
> doc, and the hda_codec.h you mentioned. Interestingly, when I
> configure all 3 jacks (via user_pin_configs) to be of type HP_OUT,
> only 1 of them will be configured as that, the other 2 will not. There
> must be something in the generic code that prevents more than 1 jack
> being configured as HP_OUT. Looking at patch_realtek.c it appears the
> norm is to set only 1 jack to be HP.

There are some restrictions for automatic parser.  The STAC/IDT
parser supports dual headphones, but realtek one doesn't, so far.
But, anyway 3 headphones are wrong.

Note that by setting the pins to HP, you get the amp boost in the
codec chip, but it doesn't mean it's better audio quality.  For
line-outs, you shouldn't put such an amp usually.


Takashi