linux-kernel - [PATCH v2] HID: lenovo: fixup Lenovo Yoga Slim 7x Keyboard rdesc

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Message-ID: <aPM1I35YXWlabuKQ@mail.hacktheplanet.fi>
Date: Sat, 18 Oct 2025 15:35:15 +0900
From: Lauri Tirkkonen <lauri@...ktheplanet.fi>
To: Jiri Kosina <jikos@...nel.org>, Benjamin Tissoires <bentiss@...nel.org>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] HID: lenovo: fixup Lenovo Yoga Slim 7x Keyboard rdesc

The keyboard of this device has the following in its report description
for Usage (Keyboard) in Collection (Application):

	# 0x15, 0x00,                    //  Logical Minimum (0)                52
	# 0x25, 0x65,                    //  Logical Maximum (101)              54
	# 0x05, 0x07,                    //  Usage Page (Keyboard)              56
	# 0x19, 0x00,                    //  Usage Minimum (0)                  58
	# 0x29, 0xdd,                    //  Usage Maximum (221)                60
	# 0x81, 0x00,                    //  Input (Data,Arr,Abs)               62

Since the Usage Min/Max range exceeds the Logical Min/Max range,
keypresses outside the Logical range are not recognized. This includes,
for example, the Japanese language keyboard variant's keys for |, _ and
\.

Fixup the report description to make the Logical range match the Usage
range, fixing the interpretation of keypresses above 101 on this device.

Signed-off-by: Lauri Tirkkonen <lauri@...ktheplanet.fi>
---
v1 -> v2: moved to hid-lenovo from hid-i2c, renamed hid-ids macro to
clarify the device only refers to the keyboard

v1: https://lore.kernel.org/all/aOdLxAEYQpV2zp77@mail.hacktheplanet.fi/

 drivers/hid/hid-ids.h    |  1 +
 drivers/hid/hid-lenovo.c | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 5721b8414bbd..4b1946eb4e7f 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -715,6 +715,7 @@
 #define USB_DEVICE_ID_ITE_LENOVO_YOGA2  0x8350
 #define I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720	0x837a
 #define USB_DEVICE_ID_ITE_LENOVO_YOGA900	0x8396
+#define I2C_DEVICE_ID_ITE_LENOVO_YOGA_SLIM_7X_KEYBOARD	0x8987
 #define USB_DEVICE_ID_ITE8595		0x8595
 #define USB_DEVICE_ID_ITE_MEDION_E1239T	0xce50
 
diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c
index 654879814f97..9cc3e029e9f6 100644
--- a/drivers/hid/hid-lenovo.c
+++ b/drivers/hid/hid-lenovo.c
@@ -148,6 +148,14 @@ static const __u8 lenovo_tpIIbtkbd_need_fixup_collection[] = {
 	0x81, 0x01,		/*   Input (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position) */
 };
 
+static const __u8 lenovo_yoga7x_kbd_need_fixup_collection[] = {
+	0x15, 0x00,	// Logical Minimum (0)
+	0x25, 0x65,	// Logical Maximum (101)
+	0x05, 0x07,	// Usage Page (Keyboard)
+	0x19, 0x00,	// Usage Minimum (0)
+	0x29, 0xDD,	// Usage Maximum (221)
+};
+
 static const __u8 *lenovo_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 		unsigned int *rsize)
 {
@@ -177,6 +185,13 @@ static const __u8 *lenovo_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 			rdesc[260] = 0x01; /* report count (2) = 0x01 */
 		}
 		break;
+	case I2C_DEVICE_ID_ITE_LENOVO_YOGA_SLIM_7X_KEYBOARD:
+		if (*rsize == 176 &&
+		    memcmp(&rdesc[52], lenovo_yoga7x_kbd_need_fixup_collection,
+			  sizeof(lenovo_yoga7x_kbd_need_fixup_collection)) == 0) {
+			rdesc[55] = rdesc[61]; // logical maximum = usage maximum
+		}
+		break;
 	}
 	return rdesc;
 }
@@ -1538,6 +1553,8 @@ static const struct hid_device_id lenovo_devices[] = {
 		     USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_X12_TAB) },
 	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 		     USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_X12_TAB2) },
+	{ HID_DEVICE(BUS_I2C, HID_GROUP_GENERIC,
+		     USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_YOGA_SLIM_7X_KEYBOARD) },
 	{ }
 };
 
-- 
2.51.1

-- 
Lauri Tirkkonen | lotheac @ IRCnet