ALSA: hda - Support multiple digital outs with auto-probing

Added the support of multiple digital outputs via auto-probing for
Realtek ALC88x codecs.  The multiple outputs are handled as slave
streams, so only one PCM stream (and the corresponding IEC958*
elements) is provided to control both digital outputs.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_realtek.c

@@ -279,6 +279,7 @@ struct alc_spec {
 					 * dig_out_nid and hp_nid are optional
 					 */
 	hda_nid_t alt_dac_nid;
+	hda_nid_t slave_dig_outs[3];	/* optional - for auto-parsing */
 	int dig_out_type;
 
 	/* capture */
@@ -4269,7 +4270,7 @@ static void alc880_auto_init_analog_input(struct hda_codec *codec)
 static int alc880_parse_auto_config(struct hda_codec *codec)
 {
 	struct alc_spec *spec = codec->spec;
-	int err;
+	int i, err;
 	static hda_nid_t alc880_ignore[] = { 0x1d, 0 };
 
 	err = snd_hda_parse_pin_def_config(codec, &spec->autocfg,
@@ -4300,8 +4301,23 @@ static int alc880_parse_auto_config(struct hda_codec *codec)
 
 	spec->multiout.max_channels = spec->multiout.num_dacs * 2;
 
-	if (spec->autocfg.dig_outs)
-		spec->multiout.dig_out_nid = ALC880_DIGOUT_NID;
+	/* check multiple SPDIF-out (for recent codecs) */
+	for (i = 0; i < spec->autocfg.dig_outs; i++) {
+		hda_nid_t dig_nid;
+		err = snd_hda_get_connections(codec,
+					      spec->autocfg.dig_out_pins[i],
+					      &dig_nid, 1);
+		if (err < 0)
+			continue;
+		if (!i)
+			spec->multiout.dig_out_nid = dig_nid;
+		else {
+			spec->multiout.slave_dig_outs = spec->slave_dig_outs;
+			spec->slave_dig_outs[i - 1] = dig_nid;
+			if (i == ARRAY_SIZE(spec->slave_dig_outs) - 1)
+				break;
+		}
+	}
 	if (spec->autocfg.dig_in_pin)
 		spec->dig_in_nid = ALC880_DIGIN_NID;