ALSA: hda/realtek: Add alc256-samsung-headphone fixup

This fixes the near-silence of the headphone jack on the ALC256-based
Samsung Galaxy Book Flex Alpha (NP730QCJ). The magic verbs were found
through trial and error, using known ALC298 hacks as inspiration. The
fixup is auto-enabled only when the NP730QCJ is detected. It can be
manually enabled using model=alc256-samsung-headphone.
Signed-off-by: Matt Kramer <mccleetus@gmail.com>
Link: https://lore.kernel.org/r/3168355.aeNJFYEL58@linusSigned-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/hd-audio/models.rst

@@ -261,6 +261,10 @@ alc-sense-combo
 huawei-mbx-stereo
     Enable initialization verbs for Huawei MBX stereo speakers;
     might be risky, try this at your own risk
+alc298-samsung-headphone
+    Samsung laptops with ALC298
+alc256-samsung-headphone
+    Samsung laptops with ALC256
 
 ALC66x/67x/892
 ==============

sound/pci/hda/patch_realtek.c

@@ -6958,6 +6958,7 @@ enum {
 	ALC236_FIXUP_HP_MUTE_LED,
 	ALC236_FIXUP_HP_MUTE_LED_MICMUTE_VREF,
 	ALC298_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET,
+	ALC256_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET,
 	ALC295_FIXUP_ASUS_MIC_NO_PRESENCE,
 	ALC269VC_FIXUP_ACER_VCOPPERBOX_PINS,
 	ALC269VC_FIXUP_ACER_HEADSET_MIC,
@@ -8286,6 +8287,14 @@ static const struct hda_fixup alc269_fixups[] = {
 			{ }
 		},
 	},
+	[ALC256_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET] = {
+		.type = HDA_FIXUP_VERBS,
+		.v.verbs = (const struct hda_verb[]) {
+			{ 0x20, AC_VERB_SET_COEF_INDEX, 0x08},
+			{ 0x20, AC_VERB_SET_PROC_COEF, 0x2fcf},
+			{ }
+		},
+	},
 	[ALC295_FIXUP_ASUS_MIC_NO_PRESENCE] = {
 		.type = HDA_FIXUP_PINS,
 		.v.pins = (const struct hda_pintbl[]) {
@@ -9099,6 +9108,7 @@ static const struct snd_pci_quirk alc269_fixup_tbl[] = {
 	SND_PCI_QUIRK(0x144d, 0xc740, "Samsung Ativ book 8 (NP870Z5G)", ALC269_FIXUP_ATIV_BOOK_8),
 	SND_PCI_QUIRK(0x144d, 0xc812, "Samsung Notebook Pen S (NT950SBE-X58)", ALC298_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET),
 	SND_PCI_QUIRK(0x144d, 0xc830, "Samsung Galaxy Book Ion (NT950XCJ-X716A)", ALC298_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET),
+	SND_PCI_QUIRK(0x144d, 0xc832, "Samsung Galaxy Book Flex Alpha (NP730QCJ)", ALC256_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET),
 	SND_PCI_QUIRK(0x1458, 0xfa53, "Gigabyte BXBT-2807", ALC283_FIXUP_HEADSET_MIC),
 	SND_PCI_QUIRK(0x1462, 0xb120, "MSI Cubi MS-B120", ALC283_FIXUP_HEADSET_MIC),
 	SND_PCI_QUIRK(0x1462, 0xb171, "Cubi N 8GL (MS-B171)", ALC283_FIXUP_HEADSET_MIC),
@@ -9445,6 +9455,7 @@ static const struct hda_model_fixup alc269_fixup_models[] = {
 	{.id = ALC298_FIXUP_HUAWEI_MBX_STEREO, .name = "huawei-mbx-stereo"},
 	{.id = ALC256_FIXUP_MEDION_HEADSET_NO_PRESENCE, .name = "alc256-medion-headset"},
 	{.id = ALC298_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET, .name = "alc298-samsung-headphone"},
+	{.id = ALC256_FIXUP_SAMSUNG_HEADPHONE_VERY_QUIET, .name = "alc256-samsung-headphone"},
 	{.id = ALC255_FIXUP_XIAOMI_HEADSET_MIC, .name = "alc255-xiaomi-headset"},
 	{.id = ALC274_FIXUP_HP_MIC, .name = "alc274-hp-mic-detect"},
 	{.id = ALC245_FIXUP_HP_X360_AMP, .name = "alc245-hp-x360-amp"},