[PATCH] ALSA: hda - Disable AA-loopback on ALC668

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

Disable the AA-loopback path to get rid of the constant white noise
that can be heard when headphones are used.

This patch was tested only on a Dell XPS13 9333.

Fix based on d2e92709e88d ("ALSA: hda - Disable AA-loopback on ALC283
Chromebook").

Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
---
 sound/pci/hda/patch_realtek.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 5f7c765..21c94e4 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -5690,6 +5690,13 @@ static int patch_alc662(struct hda_codec *codec)
 	if (has_cdefine_beep(codec))
 		spec->gen.beep_nid = 0x01;
 
+	switch (codec->vendor_id) {
+	case 0x10ec0668:
+		/* Disable AA-loopback as it causes white noise */
+		spec->gen.mixer_nid = 0;
+		break;
+	}
+
 	if ((alc_get_coef0(codec) & (1 << 14)) &&
 	    codec->bus->pci && codec->bus->pci->subsystem_vendor == 0x1025 &&
 	    spec->cdefine.platform_type == 1) {
-- 
2.0.0.rc2