ALSA: hda - limit internal mic boost for Asus X202E

When the input gain for the internal mic is set to its maximum level,
the background noise becomes so high - and any relevant signal clipped -
that the setting becomes unusable. It is better to limit the amplification.

BugLink: https://bugs.launchpad.net/bugs/1052460
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Cc: <stable@vger.kernel.org> [v3.5+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_via.c

@@ -3666,6 +3666,32 @@ static void set_widgets_power_state_vt2002P(struct hda_codec *codec)
 		update_power_state(codec, 0x21, AC_PWRST_D3);
 }
 
+/*
+ * pin fix-up
+ */
+enum {
+	VIA_FIXUP_INTMIC_BOOST,
+};
+
+static void via_fixup_intmic_boost(struct hda_codec *codec,
+				  const struct hda_fixup *fix, int action)
+{
+	if (action == HDA_FIXUP_ACT_PRE_PROBE)
+		override_mic_boost(codec, 0x30, 0, 2, 40);
+}
+
+static const struct hda_fixup via_fixups[] = {
+	[VIA_FIXUP_INTMIC_BOOST] = {
+		.type = HDA_FIXUP_FUNC,
+		.v.func = via_fixup_intmic_boost,
+	},
+};
+
+static const struct snd_pci_quirk vt2002p_fixups[] = {
+	SND_PCI_QUIRK(0x1043, 0x8532, "Asus X202E", VIA_FIXUP_INTMIC_BOOST),
+	{}
+};
+
 /* patch for vt2002P */
 static int patch_vt2002P(struct hda_codec *codec)
 {
@@ -3682,6 +3708,9 @@ static int patch_vt2002P(struct hda_codec *codec)
 	override_mic_boost(codec, 0x29, 0, 3, 40);
 	add_secret_dac_path(codec);
 
+	snd_hda_pick_fixup(codec, NULL, vt2002p_fixups, via_fixups);
+	snd_hda_apply_fixup(codec, HDA_FIXUP_ACT_PRE_PROBE);
+
 	/* automatic parse from the BIOS config */
 	err = via_parse_auto_config(codec);
 	if (err < 0) {