The internal mic input is phase inverted on one channel.
To avoid people in userspace summing the channels together
and get zero result, use a separate mixer control for the
inverted channel.

BugLink: https://bugs.launchpad.net/bugs/903853
Signed-off-by: David Henningsson <email address hidden>
---
 sound/pci/hda/patch_conexant.c |   88 ++++++++++++++++++++++++++++++++++------
 1 files changed, 75 insertions(+), 13 deletions(-)

diff --git a/sound/pci/hda/patch_conexant.c b/sound/pci/hda/patch_conexant.c
index e6eafb1..c18e3b1 100644
--- a/sound/pci/hda/patch_conexant.c
+++ b/sound/pci/hda/patch_conexant.c
@@ -142,6 +142,7 @@ struct conexant_spec {
 	unsigned int asus:1;
 	unsigned int pin_eapd_ctrls:1;
 	unsigned int single_adc_amp:1;
+	unsigned int fixup_stereo_dmic:1;
 
 	unsigned int adc_switching:1;
 
@@ -4107,9 +4108,9 @@ static int cx_auto_init(struct hda_codec *codec)
 
 static int cx_auto_add_volume_idx(struct hda_codec *codec, const char *basename,
 			      const char *dir, int cidx,
-			      hda_nid_t nid, int hda_dir, int amp_idx)
+			      hda_nid_t nid, int hda_dir, int amp_idx, int chs)
 {
-	static char name[32];
+	static char name[44];
 	static struct snd_kcontrol_new knew[] = {
 		HDA_CODEC_VOLUME(name, 0, 0, 0),
 		HDA_CODEC_MUTE(name, 0, 0, 0),
@@ -4119,7 +4120,7 @@ static int cx_auto_add_volume_idx(struct hda_codec *codec, const char *basename,
 
 	for (i = 0; i < 2; i++) {
 		struct snd_kcontrol *kctl;
-		knew[i].private_value = HDA_COMPOSE_AMP_VAL(nid, 3, amp_idx,
+		knew[i].private_value = HDA_COMPOSE_AMP_VAL(nid, chs, amp_idx,
 							    hda_dir);
 		knew[i].subdevice = HDA_SUBDEV_AMP_FLAG;
 		knew[i].index = cidx;
@@ -4138,7 +4139,7 @@ static int cx_auto_add_volume_idx(struct hda_codec *codec, const char *basename,
 }
 
 #define cx_auto_add_volume(codec, str, dir, cidx, nid, hda_dir)		\
-	cx_auto_add_volume_idx(codec, str, dir, cidx, nid, hda_dir, 0)
+	cx_auto_add_volume_idx(codec, str, dir, cidx, nid, hda_dir, 0, 3)
 
 #define cx_auto_add_pb_volume(codec, nid, str, idx)			\
 	cx_auto_add_volume(codec, str, " Playback", idx, nid, HDA_OUTPUT)
@@ -4208,6 +4209,36 @@ static int cx_auto_build_output_controls(struct hda_codec *codec)
 	return 0;
 }
 
+/* Returns zero if this is a normal stereo channel, and non-zero if it should
+   be split in two independent channels.
+   dest_label must be at least 44 characters. */
+static int cx_auto_get_rightch_label(struct hda_codec *codec, const char *label,
+				     char *dest_label, int nid)
+{
+	struct conexant_spec *spec = codec->spec;
+	int i;
+
+	if (!spec->fixup_stereo_dmic)
+		return 0;
+
+	for (i = 0; i < AUTO_CFG_MAX_INS; i++) {
+		int def_conf;
+		if (spec->autocfg.inputs[i].pin != nid)
+			continue;
+
+		if (spec->autocfg.inputs[i].type != AUTO_PIN_MIC)
+			return 0;
+		def_conf = snd_hda_codec_get_pincfg(codec, nid);
+		if (snd_hda_get_input_pin_attr(def_conf) != INPUT_PIN_ATTR_INT)
+			return 0;
+
+		/* Finally found the inverted internal mic! */
+		snprintf(dest_label, 44, "Inverted %s", label);
+		return 1;
+	}
+	return 0;
+}
+
 static int cx_auto_add_capture_volume(struct hda_codec *codec, hda_nid_t nid,
 				      const char *label, const char *pfx,
 				      int cidx)
@@ -4216,14 +4247,25 @@ static int cx_auto_add_capture_volume(struct hda_codec *codec, hda_nid_t nid,
 	int i;
 
 	for (i = 0; i < spec->num_adc_nids; i++) {
+		char rightch_label[44];
 		hda_nid_t adc_nid = spec->adc_nids[i];
 		int idx = get_input_connection(codec, adc_nid, nid);
 		if (idx < 0)
 			continue;
 		if (spec->single_adc_amp)
 			idx = 0;
+
+		if (cx_auto_get_rightch_label(codec, label, rightch_label, nid)) {
+			/* Make two independent kcontrols for left and right */
+			int err = cx_auto_add_volume_idx(codec, label, pfx,
+					      cidx, adc_nid, HDA_INPUT, idx, 1);
+			if (err < 0)
+				return err;
+			return cx_auto_add_volume_idx(codec, rightch_label, pfx,
+						      cidx, adc_nid, HDA_INPUT, idx, 2);
+		}
 		return cx_auto_add_volume_idx(codec, label, pfx,
-					      cidx, adc_nid, HDA_INPUT, idx);
+					      cidx, adc_nid, HDA_INPUT, idx, 3);
 	}
 	return 0;
 }
@@ -4236,9 +4278,19 @@ static int cx_auto_add_boost_volume(struct hda_codec *codec, int idx,
 	int i, con;
 
 	nid = spec->imux_info[idx].pin;
-	if (get_wcaps(codec, nid) & AC_WCAP_IN_AMP)
+	if (get_wcaps(codec, nid) & AC_WCAP_IN_AMP) {
+		char rightch_label[44];
+		if (cx_auto_get_rightch_label(codec, label, rightch_label, nid)) {
+			int err = cx_auto_add_volume_idx(codec, label, " Boost",
+							 cidx, nid, HDA_INPUT, 0, 1);
+			if (err < 0)
+				return err;
+			return cx_auto_add_volume_idx(codec, rightch_label, " Boost",
+						      cidx, nid, HDA_INPUT, 0, 2);
+		}
 		return cx_auto_add_volume(codec, label, " Boost", cidx,
 					  nid, HDA_INPUT);
+	}
 	con = __select_input_connection(codec, spec->imux_info[idx].adc, nid,
 					&mux, false, 0);
 	if (con < 0)
@@ -4405,22 +4457,30 @@ static void apply_pincfg(struct hda_codec *codec, const struct cxt_pincfg *cfg)
 
 }
 
-static void apply_pin_fixup(struct hda_codec *codec,
+enum {
+	CXT_PINCFG_LENOVO_X200,
+	CXT_FIXUP_STEREO_DMIC,
+};
+
+static void apply_fixup(struct hda_codec *codec,
 			    const struct snd_pci_quirk *quirk,
 			    const struct cxt_pincfg **table)
 {
+	struct conexant_spec *spec = codec->spec;
+
 	quirk = snd_pci_quirk_lookup(codec->bus->pci, quirk);
-	if (quirk) {
+	if (quirk && table[quirk->value]) {
 		snd_printdd(KERN_INFO "hda_codec: applying pincfg for %s\n",
 			    quirk->name);
 		apply_pincfg(codec, table[quirk->value]);
 	}
+	if (quirk->value == CXT_FIXUP_STEREO_DMIC) {
+		snd_printdd(KERN_INFO "hda_codec: applying internal mic workaround for %s\n",
+			    quirk->name);
+		spec->fixup_stereo_dmic = 1;
+	}
 }
 
-enum {
-	CXT_PINCFG_LENOVO_X200,
-};
-
 static const struct cxt_pincfg cxt_pincfg_lenovo_x200[] = {
 	{ 0x16, 0x042140ff }, /* HP (seq# overridden) */
 	{ 0x17, 0x21a11000 }, /* dock-mic */
@@ -4431,10 +4491,12 @@ static const struct cxt_pincfg cxt_pincfg_lenovo_x200[] = {
 
 static const struct cxt_pincfg *cxt_pincfg_tbl[] = {
 	[CXT_PINCFG_LENOVO_X200] = cxt_pincfg_lenovo_x200,
+	[CXT_FIXUP_STEREO_DMIC] = NULL,
 };
 
 static const struct snd_pci_quirk cxt_fixups[] = {
 	SND_PCI_QUIRK(0x17aa, 0x20f2, "Lenovo X200", CXT_PINCFG_LENOVO_X200),
+	SND_PCI_QUIRK(0x17aa, 0x3975, "Lenovo U300s", CXT_FIXUP_STEREO_DMIC),
 	{}
 };
 
@@ -4477,7 +4539,7 @@ static int patch_conexant_auto(struct hda_codec *codec)
 		break;
 	}
 
-	apply_pin_fixup(codec, cxt_fixups, cxt_pincfg_tbl);
+	apply_fixup(codec, cxt_fixups, cxt_pincfg_tbl);
 
 	/* Show mute-led control only on HP laptops
 	 * This is a sort of white-list: on HP laptops, EAPD corresponds
-- 
1.7.9.1