ALSA: hda - Fix click noise at start on Dell XPS13

Dell XPS13 produces a click noise at boot up, and Gabriele spotted out
that it's triggered by the initial pin control of the mic (NID 0x19).
This has to be set to Hi-Z Vref while the driver initializes to Vref
80% as a normal mic.

This patch fixes the generic parser code not to override the target
vref if it has been already set by the driver, and adds a proper
initialization of the target vref for this pin in the Realtek driver
side.
Reported-and-tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_generic.c

@@ -3259,7 +3259,8 @@ static int create_input_ctls(struct hda_codec *codec)
 		val = PIN_IN;
 		if (cfg->inputs[i].type == AUTO_PIN_MIC)
 			val |= snd_hda_get_default_vref(codec, pin);
-		if (pin != spec->hp_mic_pin)
+		if (pin != spec->hp_mic_pin &&
+		    !snd_hda_codec_get_pin_target(codec, pin))
 			set_pin_target(codec, pin, val, false);
 
 		if (mixer) {

sound/pci/hda/patch_realtek.c

@@ -4190,11 +4190,18 @@ static void alc_shutup_dell_xps13(struct hda_codec *codec)
 static void alc_fixup_dell_xps13(struct hda_codec *codec,
 				const struct hda_fixup *fix, int action)
 {
-	if (action == HDA_FIXUP_ACT_PROBE) {
-		struct alc_spec *spec = codec->spec;
-		struct hda_input_mux *imux = &spec->gen.input_mux;
-		int i;
+	struct alc_spec *spec = codec->spec;
+	struct hda_input_mux *imux = &spec->gen.input_mux;
+	int i;
 
+	switch (action) {
+	case HDA_FIXUP_ACT_PRE_PROBE:
+		/* mic pin 0x19 must be initialized with Vref Hi-Z, otherwise
+		 * it causes a click noise at start up
+		 */
+		snd_hda_codec_set_pin_target(codec, 0x19, PIN_VREFHIZ);
+		break;
+	case HDA_FIXUP_ACT_PROBE:
 		spec->shutup = alc_shutup_dell_xps13;
 
 		/* Make the internal mic the default input source. */
@@ -4204,6 +4211,7 @@ static void alc_fixup_dell_xps13(struct hda_codec *codec,
 				break;
 			}
 		}
+		break;
 	}
 }