[ALSA] hda-codec - Disable shared stream on AD1986A

AD1986A has a hardware problem that it cannot share a stream with
multiple pins properly.  The problem occurs e.g. when a volume is changed
during playback.
So far, hda-intel driver unconditionally assigns the stream to multiple
output pins in copy-front mode, and this should be avoided for AD1986A
codec.
The original fix patch was by zhejiang <zhe.jiang@intel.com>.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

sound/pci/hda/hda_codec.c

@@ -2485,13 +2485,14 @@ int snd_hda_multi_out_analog_prepare(struct hda_codec *codec,
 	/* front */
 	snd_hda_codec_setup_stream(codec, nids[HDA_FRONT], stream_tag,
 				   0, format);
-	if (mout->hp_nid && mout->hp_nid != nids[HDA_FRONT])
+	if (!mout->no_share_stream &&
+	    mout->hp_nid && mout->hp_nid != nids[HDA_FRONT])
 		/* headphone out will just decode front left/right (stereo) */
 		snd_hda_codec_setup_stream(codec, mout->hp_nid, stream_tag,
 					   0, format);
 	/* extra outputs copied from front */
 	for (i = 0; i < ARRAY_SIZE(mout->extra_out_nid); i++)
-		if (mout->extra_out_nid[i])
+		if (!mout->no_share_stream && mout->extra_out_nid[i])
 			snd_hda_codec_setup_stream(codec,
 						   mout->extra_out_nid[i],
 						   stream_tag, 0, format);
@@ -2501,7 +2502,7 @@ int snd_hda_multi_out_analog_prepare(struct hda_codec *codec,
 		if (chs >= (i + 1) * 2) /* independent out */
 			snd_hda_codec_setup_stream(codec, nids[i], stream_tag,
 						   i * 2, format);
-		else /* copy front */
+		else if (!mout->no_share_stream) /* copy front */
 			snd_hda_codec_setup_stream(codec, nids[i], stream_tag,
 						   0, format);
 	}

sound/pci/hda/hda_local.h

@@ -220,6 +220,7 @@ struct hda_multi_out {
 	hda_nid_t dig_out_nid;	/* digital out audio widget */
 	int max_channels;	/* currently supported analog channels */
 	int dig_out_used;	/* current usage of digital out (HDA_DIG_XXX) */
+	int no_share_stream;	/* don't share a stream with multiple pins */
 };
 
 int snd_hda_multi_out_dig_open(struct hda_codec *codec,

sound/pci/hda/patch_analog.c

@@ -957,6 +957,14 @@ static int patch_ad1986a(struct hda_codec *codec)
 		break;
 	}
 
+	/* AD1986A has a hardware problem that it can't share a stream
+	 * with multiple output pins.  The copy of front to surrounds
+	 * causes noisy or silent outputs at a certain timing, e.g.
+	 * changing the volume.
+	 * So, let's disable the shared stream.
+	 */
+	spec->multiout.no_share_stream = 1;
+
 	return 0;
 }