[alsa-devel] [PATCH 6/7] HDA patch_via.c: Independent DAC for headphone

[Takashi Iwai]

At Tue, 9 Sep 2008 15:58:27 +0800,
Harald Welte wrote:
> 
> [ALSA] HDA VIA: Add "Independent Headphone" mode
> 
> This mode allows an output stream to have two substreams, one for the
> speakers and one for the headphone.  Each of the substreams has independent
> PCM data and uses a different DAC.
> 
> Signed-off-by: Harald Welte <HaraldWelte at viatech.com>
> 
> Index: linux-2.6/sound/pci/hda/patch_via.c
> ===================================================================
> --- linux-2.6.orig/sound/pci/hda/patch_via.c
> +++ linux-2.6/sound/pci/hda/patch_via.c
> @@ -33,6 +33,7 @@
>  /* 2008-02-03  Lydia Wang  Fix Rear channels and Back channels inverse issue */
>  /* 2008-03-06  Lydia Wang  Add VT1702 codec and VT1708S codec support        */
>  /* 2008-04-09  Lydia Wang  Add mute front speaker when HP plugin             */
> +/* 2008-04-09  Lydia Wang  Add Independent HP feature                        */
>  /*                                                                           */
>  /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
>  
> @@ -41,6 +42,7 @@
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <sound/core.h>
> +#include <sound/asoundef.h>
>  #include "hda_codec.h"
>  #include "hda_local.h"
>  #include "hda_patch.h"
> @@ -140,9 +142,13 @@
>  	struct auto_pin_cfg autocfg;
>  	unsigned int num_kctl_alloc, num_kctl_used;
>  	struct snd_kcontrol_new *kctl_alloc;
> -	struct hda_input_mux private_imux;
> +	struct hda_input_mux private_imux[2];
>  	hda_nid_t private_dac_nids[AUTO_CFG_MAX_OUTS];
>  
> +	/* HP mode source */
> +	const struct hda_input_mux *hp_mux;
> +	unsigned int hp_independent_mode;
> +
>  #ifdef CONFIG_SND_HDA_POWER_SAVE
>  	struct hda_loopback_check loopback;
>  #endif
> @@ -326,6 +332,92 @@
>  					     &spec->cur_mux[adc_idx]);
>  }
>  
> +static int via_independent_hp_info(struct snd_kcontrol *kcontrol,
> +				   struct snd_ctl_elem_info *uinfo)
> +{
> +	struct hda_codec *codec = snd_kcontrol_chip(kcontrol);
> +	struct via_spec *spec = codec->spec;
> +	return snd_hda_input_mux_info(spec->hp_mux, uinfo);
> +}

Usually this kind of "switch" is implemented as a boolean switch
since some mixer apps aren't capable to handle enum controls.

If you'd like to change to that, please send an additional patch
as I already committed these.


thanks,

Takashi