[PATCH v2] ALSA: hda/realtek: Add quirk for Dell Latitude 7520

[Gabriele Mazzotta <gabriele.mzt@gmail.com>]

The driver is currently using ALC269_FIXUP_DELL4_MIC_NO_PRESENCE for
the Latitude 7520, but this fixup chain has some issues:

 - The internal mic is really loud and the recorded audio is distorted
   at "standard" audio levels.

 - There are pop noises at system startup and when plugging/unplugging
   headphone jacks.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215885
Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
---
 sound/pci/hda/patch_realtek.c | 43 +++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 62fbf3772b41..36920570660b 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -6780,6 +6780,41 @@ static void alc256_fixup_mic_no_presence_and_resume(struct hda_codec *codec,
 	}
 }
 
+static void alc_fixup_dell4_mic_no_presence_quiet(struct hda_codec *codec,
+						  const struct hda_fixup *fix,
+						  int action)
+{
+	struct alc_spec *spec = codec->spec;
+	struct hda_input_mux *imux = &spec->gen.input_mux;
+	int i;
+
+	alc269_fixup_limit_int_mic_boost(codec, fix, action);
+
+	switch (action) {
+	case HDA_FIXUP_ACT_PRE_PROBE:
+		/**
+		 * Set the vref of pin 0x19 (Headset Mic) and pin 0x1b (Headphone Mic)
+		 * to Hi-Z to avoid pop noises at startup and when plugging and
+		 * unplugging headphones.
+		 */
+		snd_hda_codec_set_pin_target(codec, 0x19, PIN_VREFHIZ);
+		snd_hda_codec_set_pin_target(codec, 0x1b, PIN_VREFHIZ);
+		break;
+	case HDA_FIXUP_ACT_PROBE:
+		/**
+		 * Make the internal mic (0x12) the default input source to
+		 * prevent pop noises on cold boot.
+		 */
+		for (i = 0; i < imux->num_items; i++) {
+			if (spec->gen.imux_pins[i] == 0x12) {
+				spec->gen.cur_mux[0] = i;
+				break;
+			}
+		}
+		break;
+	}
+}
+
 enum {
 	ALC269_FIXUP_GPIO2,
 	ALC269_FIXUP_SONY_VAIO,
@@ -6821,6 +6856,7 @@ enum {
 	ALC269_FIXUP_DELL2_MIC_NO_PRESENCE,
 	ALC269_FIXUP_DELL3_MIC_NO_PRESENCE,
 	ALC269_FIXUP_DELL4_MIC_NO_PRESENCE,
+	ALC269_FIXUP_DELL4_MIC_NO_PRESENCE_QUIET,
 	ALC269_FIXUP_HEADSET_MODE,
 	ALC269_FIXUP_HEADSET_MODE_NO_HP_MIC,
 	ALC269_FIXUP_ASPIRE_HEADSET_MIC,
@@ -8799,6 +8835,12 @@ static const struct hda_fixup alc269_fixups[] = {
 		.chained = true,
 		.chain_id = ALC285_FIXUP_HP_MUTE_LED,
 	},
+	[ALC269_FIXUP_DELL4_MIC_NO_PRESENCE_QUIET] = {
+		.type = HDA_FIXUP_FUNC,
+		.v.func = alc_fixup_dell4_mic_no_presence_quiet,
+		.chained = true,
+		.chain_id = ALC269_FIXUP_DELL4_MIC_NO_PRESENCE,
+	},
 };
 
 static const struct snd_pci_quirk alc269_fixup_tbl[] = {
@@ -8889,6 +8931,7 @@ static const struct snd_pci_quirk alc269_fixup_tbl[] = {
 	SND_PCI_QUIRK(0x1028, 0x09bf, "Dell Precision", ALC233_FIXUP_ASUS_MIC_NO_PRESENCE),
 	SND_PCI_QUIRK(0x1028, 0x0a2e, "Dell", ALC236_FIXUP_DELL_AIO_HEADSET_MIC),
 	SND_PCI_QUIRK(0x1028, 0x0a30, "Dell", ALC236_FIXUP_DELL_AIO_HEADSET_MIC),
+	SND_PCI_QUIRK(0x1028, 0x0a38, "Dell Latitude 7520", ALC269_FIXUP_DELL4_MIC_NO_PRESENCE_QUIET),
 	SND_PCI_QUIRK(0x1028, 0x0a58, "Dell", ALC255_FIXUP_DELL_HEADSET_MIC),
 	SND_PCI_QUIRK(0x1028, 0x0a61, "Dell XPS 15 9510", ALC289_FIXUP_DUAL_SPK),
 	SND_PCI_QUIRK(0x1028, 0x0a62, "Dell Precision 5560", ALC289_FIXUP_DUAL_SPK),
-- 
2.36.0