[PATCH 1/1] ALSA: hda/realtek: fix mic boost on Intel NUC 8

[Phil Calvin]

Fix two bugs with the Intel HDA Realtek ALC233 sound codec
present in Intel NUC NUC8i7BEH and probably a few other similar
NUC models.

These codecs advertise a 4-level microphone input boost amplifier on
pin 0x19, but the highest two boost settings do not work correctly,
and produce only low analog noise that does not seem to contain any
discernible signal. There is an existing fixup for this exact problem
but for a different PCI subsystem ID, so we re-use that logic.

Changing the boost level also triggers a DC spike in the input signal
that bleeds off over about a second and overwhelms any input during
that time. Thankfully, the existing fixup has the side effect of
making the boost control show up in userspace as a mute/unmute switch,
and this keeps (e.g.) PulseAudio from fiddling with it during normal
input volume adjustments.

Finally, the NUC hardware has built-in inverted stereo mics. This
patch also enables the usual fixup for this so the two channels cancel
noise instead of the actual signal.

Signed-off-by: Phil Calvin <phil at philcalvin.com>
---
  sound/pci/hda/patch_realtek.c | 13 +++++++++++++
  1 file changed, 13 insertions(+)

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 58946d069ee5..e1fd4c81965a 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -6405,6 +6405,8 @@ enum {
  	ALC269_FIXUP_LEMOTE_A1802,
  	ALC269_FIXUP_LEMOTE_A190X,
  	ALC256_FIXUP_INTEL_NUC8_RUGGED,
+	ALC233_FIXUP_INTEL_NUC8_DMIC,
+	ALC233_FIXUP_INTEL_NUC8_BOOST,
  	ALC256_FIXUP_INTEL_NUC10,
  	ALC255_FIXUP_XIAOMI_HEADSET_MIC,
  	ALC274_FIXUP_HP_MIC,
@@ -7122,6 +7124,16 @@ static const struct hda_fixup alc269_fixups[] = {
  		.type = HDA_FIXUP_FUNC,
  		.v.func = alc233_fixup_lenovo_line2_mic_hotkey,
  	},
+	[ALC233_FIXUP_INTEL_NUC8_DMIC] = {
+		.type = HDA_FIXUP_FUNC,
+		.v.func = alc_fixup_inv_dmic,
+		.chained = true,
+		.chain_id = ALC233_FIXUP_INTEL_NUC8_BOOST,
+	},
+	[ALC233_FIXUP_INTEL_NUC8_BOOST] = {
+		.type = HDA_FIXUP_FUNC,
+		.v.func = alc269_fixup_limit_int_mic_boost
+	},
  	[ALC255_FIXUP_DELL_SPK_NOISE] = {
  		.type = HDA_FIXUP_FUNC,
  		.v.func = alc_fixup_disable_aamix,
@@ -8265,6 +8277,7 @@ static const struct snd_pci_quirk 
alc269_fixup_tbl[] = {
  	SND_PCI_QUIRK(0x1c06, 0x2013, "Lemote A1802", ALC269_FIXUP_LEMOTE_A1802),
  	SND_PCI_QUIRK(0x1c06, 0x2015, "Lemote A190X", ALC269_FIXUP_LEMOTE_A190X),
  	SND_PCI_QUIRK(0x8086, 0x2080, "Intel NUC 8 Rugged", 
ALC256_FIXUP_INTEL_NUC8_RUGGED),
+	SND_PCI_QUIRK(0x8086, 0x2074, "Intel NUC 8", 
ALC233_FIXUP_INTEL_NUC8_DMIC),
  	SND_PCI_QUIRK(0x8086, 0x2081, "Intel NUC 10", ALC256_FIXUP_INTEL_NUC10),
   #if 0
-- 
2.30.2