ALSA: hda - Fix digital-mic mono recording on ASUS Eee PC

The digital-mic unit on ASUS Eee PC gives PDM signals instead of the
normal stereo PCM, thus you can't record a mono stream from the stereo
stream as is; the summed stereo signal results in almost zero level, and
you'll hear only soft noise.

As a workaround, use ALC269-specific COEF to manipulate the dmic route
for mono, like used for ALC271x.  This is implemented as a fix-up, thus
it works only with model=auto or without REALTEK_QUIRKS Kconfig.

Reported-and-tested-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 26 insertions, 0 deletions

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index e125c60fe352..9a1aa09f47fe 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -4484,6 +4484,22 @@ static void alc269_fixup_pcm_44k(struct hda_codec *codec,
         spec->stream_analog_capture = &alc269_44k_pcm_analog_capture;
 }
 
+static void alc269_fixup_stereo_dmic(struct hda_codec *codec,
+                                     const struct alc_fixup *fix, int action)
+{
+        int coef;
+
+        if (action != ALC_FIXUP_ACT_INIT)
+                return;
+        /* The digital-mic unit sends PDM (differential signal) instead of
+         * the standard PCM, thus you can't record a valid mono stream as is.
+         * Below is a workaround specific to ALC269 to control the dmic
+         * signal source as mono.
+         */
+        coef = alc_read_coef_idx(codec, 0x07);
+        alc_write_coef_idx(codec, 0x07, coef | 0x80);
+}
+
 enum {
         ALC269_FIXUP_SONY_VAIO,
         ALC275_FIXUP_SONY_VAIO_GPIO2,
@@ -4494,6 +4510,7 @@ enum {
         ALC275_FIXUP_SONY_HWEQ,
         ALC271_FIXUP_DMIC,
         ALC269_FIXUP_PCM_44K,
+        ALC269_FIXUP_STEREO_DMIC,
 };
 
 static const struct alc_fixup alc269_fixups[] = {
@@ -4556,10 +4573,19 @@ static const struct alc_fixup alc269_fixups[] = {
                 .type = ALC_FIXUP_FUNC,
                 .v.func = alc269_fixup_pcm_44k,
         },
+        [ALC269_FIXUP_STEREO_DMIC] = {
+                .type = ALC_FIXUP_FUNC,
+                .v.func = alc269_fixup_stereo_dmic,
+        },
 };
 
 static const struct snd_pci_quirk alc269_fixup_tbl[] = {
         SND_PCI_QUIRK(0x1043, 0x1a13, "Asus G73Jw", ALC269_FIXUP_ASUS_G73JW),
+        SND_PCI_QUIRK(0x1043, 0x16e3, "ASUS UX50", ALC269_FIXUP_STEREO_DMIC),
+        SND_PCI_QUIRK(0x1043, 0x831a, "ASUS P901", ALC269_FIXUP_STEREO_DMIC),
+        SND_PCI_QUIRK(0x1043, 0x834a, "ASUS S101", ALC269_FIXUP_STEREO_DMIC),
+        SND_PCI_QUIRK(0x1043, 0x8398, "ASUS P1005", ALC269_FIXUP_STEREO_DMIC),
+        SND_PCI_QUIRK(0x1043, 0x83ce, "ASUS P1005", ALC269_FIXUP_STEREO_DMIC),
         SND_PCI_QUIRK(0x104d, 0x9073, "Sony VAIO", ALC275_FIXUP_SONY_VAIO_GPIO2),
         SND_PCI_QUIRK(0x104d, 0x907b, "Sony VAIO", ALC275_FIXUP_SONY_HWEQ),
         SND_PCI_QUIRK(0x104d, 0x9084, "Sony VAIO", ALC275_FIXUP_SONY_HWEQ),