T480: fix the headphone jack

blobs/xx80/README.md

@@ -54,3 +54,7 @@ A guide on how to flash this board (both the Heads rom and the Thunderbolt `tb.b
 https://osresearch.net/T480-maximized-flashing/
 
 The upstream documentation is available here. It includes a list of known issues: https://doc.coreboot.org/mainboard/lenovo/t480.html
+Please note that some of the listed issues have been fixed under heads by using patches that are not yet merged upstream:
+* headphone jack works as expected and is automatically detected when plugged in
+* thunderbolt works
+* lower USB-C port works

patches/coreboot-25.09/0012-mb-lenovo-t480-Fix-headphone-jack.patch

@@ -0,0 +1,79 @@
+From 95532d31c348cfa3d847885e7c4d7d2b97b1d7d7 Mon Sep 17 00:00:00 2001
+From: Arthur Heymans <arthur@aheymans.xyz>
+Date: Thu, 13 Nov 2025 15:45:46 +0100
+Subject: [PATCH] mb/lenovo/t480: Fix headphone jack
+
+Add additional register configuration for the Realtek ALC257 audio
+codec on the Lenovo ThinkPad T480. This includes:
+
+- Hidden register SW reset sequence
+- ClassD 2W amplifier configuration
+- Jack detection (JD1) setup for headphone port
+- Silence data mode threshold setting at -84dB
+
+Shamelessly taken from google/brya/variants/pujjolo/hda_verb.c
+
+Change-Id: Ib77138d782ceb9feeaef82935bc1c0d5c3066183
+Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
+---
+ .../sklkbl_thinkpad/variants/t480/hda_verb.c  | 37 ++++++++++++++++++-
+ 1 file changed, 36 insertions(+), 1 deletion(-)
+
+diff --git a/src/mainboard/lenovo/sklkbl_thinkpad/variants/t480/hda_verb.c b/src/mainboard/lenovo/sklkbl_thinkpad/variants/t480/hda_verb.c
+index 3a951ce0da..e0caff3db5 100644
+--- a/src/mainboard/lenovo/sklkbl_thinkpad/variants/t480/hda_verb.c
++++ b/src/mainboard/lenovo/sklkbl_thinkpad/variants/t480/hda_verb.c
+@@ -5,7 +5,7 @@
+ const u32 cim_verb_data[] = {
+ 	0x10ec0257, // Vendor/Device ID: Realtek ALC257
+ 	0x17aa225d, // Subsystem ID
+-	11,
++	18,
+ 	AZALIA_SUBVENDOR(0, 0x17aa225d),
+
+ 	AZALIA_PIN_CFG(0, 0x12, AZALIA_PIN_DESC(
+@@ -51,6 +51,41 @@ const u32 cim_verb_data[] = {
+ 		1, 15
+ 	)),
+
++		//==========Widget node 0x20 - 0 :Hidden register SW reset
++	0x0205001A,
++	0x0204C003,
++	0x0205001A,
++	0x0204C003,
++	0x05850000,
++	0x0584F880,
++	0x05850000,
++	0x0584F880,
++	//==========Widget node 0x20 - 1 : ClassD 2W
++	0x02050038,
++	0x02048981,
++	0x0205001B,
++	0x02040A4B,
++	//==========Widget node 0x20 - 2
++	0x0205003C,
++	0x02043154,
++	0x0205003C,
++	0x02043114,
++	//==========Widget node 0x20 - 3 :
++	0x02050046,
++	0x02040004,
++	0x05750003,
++	0x057409A3,
++	//==========Widget node 0x20 - 4 :JD1 enable 1JD port for HP JD
++	0x02050009,
++	0x02046003,
++	0x0205000A,
++	0x02047770,
++	//==========Widget node 0x20 - 5 : Silence data mode Threshold (-84dB)
++	0x02050037,
++	0x0204FE15,
++	0x02050030,
++	0x02049004,
++
+ 	0x8086280b, // Vendor/Device ID: Intel Kabylake HDMI
+ 	0x80860101, // Subsystem ID
+ 	4,
+-- 
+2.47.3
+