ALSA: hda - Exclude unusable ADCs for ALC88x

On Realtek codecs, a digital mic pin is connected often only to a single
ADC.  But the parser tries to set up all ADCs no matter whether the
digital mic is available, and results in non-selectable input source.

This patch adds a check of input-source availability of each ADC, and
excludes ones that don't support all input sources.

Reference: Novell bnc#561235
	http://bugzilla.novell.com/show_bug.cgi?id=561235

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_realtek.c

@@ -10021,10 +10021,12 @@ static int patch_alc882(struct hda_codec *codec)
 		spec->init_amp = ALC_INIT_DEFAULT; /* always initialize */
 
 	if (!spec->adc_nids && spec->input_mux) {
-		int i;
+		int i, j;
 		spec->num_adc_nids = 0;
 		for (i = 0; i < ARRAY_SIZE(alc882_adc_nids); i++) {
+			const struct hda_input_mux *imux = spec->input_mux;
 			hda_nid_t cap;
+			hda_nid_t items[16];
 			hda_nid_t nid = alc882_adc_nids[i];
 			unsigned int wcap = get_wcaps(codec, nid);
 			/* get type */
@@ -10035,6 +10037,15 @@ static int patch_alc882(struct hda_codec *codec)
 			err = snd_hda_get_connections(codec, nid, &cap, 1);
 			if (err < 0)
 				continue;
+			err = snd_hda_get_connections(codec, cap, items,
+						      ARRAY_SIZE(items));
+			if (err < 0)
+				continue;
+			for (j = 0; j < imux->num_items; j++)
+				if (imux->items[j].index >= err)
+					break;
+			if (j < imux->num_items)
+				continue;
 			spec->private_capsrc_nids[spec->num_adc_nids] = cap;
 			spec->num_adc_nids++;
 		}