Patch "HID: logitech-hidpp: Don't use the USB serial for USB devices" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    HID: logitech-hidpp: Don't use the USB serial for USB devices

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     hid-logitech-hidpp-don-t-use-the-usb-serial-for-usb-.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 4d734e033d4b99af89afb9aea2eebc9ca85ba7ea
Author: Bastien Nocera <hadess@xxxxxxxxxx>
Date:   Thu Mar 2 14:01:16 2023 +0100

    HID: logitech-hidpp: Don't use the USB serial for USB devices
    
    [ Upstream commit 7ad1fe0da0fa91bf920b79ab05ae97bfabecc4f4 ]
    
    For devices that support the 0x0003 feature (Device Information) version 4,
    set the serial based on the output of that feature, rather than relying
    on the usbhid code setting the USB serial.
    
    This should allow the serial when connected through USB to (nearly)
    match the one when connected through a unifying receiver.
    
    For example, on the serials on a G903 wired/wireless mouse:
    - Unifying: 4067-e8-ce-cd-45
    - USB before patch: 017C385C3837
    - USB after patch: c086-e8-ce-cd-45
    
    Signed-off-by: Bastien Nocera <hadess@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230302130117.3975-1-hadess@xxxxxxxxxx
    Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 504e8917b06f3..a4d9ee9170998 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -777,6 +777,55 @@ static bool hidpp_is_connected(struct hidpp_device *hidpp)
 	return ret == 0;
 }
 
+/* -------------------------------------------------------------------------- */
+/* 0x0003: Device Information                                                 */
+/* -------------------------------------------------------------------------- */
+
+#define HIDPP_PAGE_DEVICE_INFORMATION			0x0003
+
+#define CMD_GET_DEVICE_INFO				0x00
+
+static int hidpp_get_serial(struct hidpp_device *hidpp, u32 *serial)
+{
+	struct hidpp_report response;
+	u8 feature_type;
+	u8 feature_index;
+	int ret;
+
+	ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_DEVICE_INFORMATION,
+				     &feature_index,
+				     &feature_type);
+	if (ret)
+		return ret;
+
+	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
+					  CMD_GET_DEVICE_INFO,
+					  NULL, 0, &response);
+	if (ret)
+		return ret;
+
+	/* See hidpp_unifying_get_serial() */
+	*serial = *((u32 *)&response.rap.params[1]);
+	return 0;
+}
+
+static int hidpp_serial_init(struct hidpp_device *hidpp)
+{
+	struct hid_device *hdev = hidpp->hid_dev;
+	u32 serial;
+	int ret;
+
+	ret = hidpp_get_serial(hidpp, &serial);
+	if (ret)
+		return ret;
+
+	snprintf(hdev->uniq, sizeof(hdev->uniq), "%04x-%4phD",
+		 hdev->product, &serial);
+	dbg_hid("HID++ DeviceInformation: Got serial: %s\n", hdev->uniq);
+
+	return 0;
+}
+
 /* -------------------------------------------------------------------------- */
 /* 0x0005: GetDeviceNameType                                                  */
 /* -------------------------------------------------------------------------- */
@@ -3040,6 +3089,8 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	if (hidpp->quirks & HIDPP_QUIRK_UNIFYING)
 		hidpp_unifying_init(hidpp);
+	else if (hid_is_usb(hidpp->hid_dev))
+		hidpp_serial_init(hidpp);
 
 	connected = hidpp_is_connected(hidpp);
 	atomic_set(&hidpp->connected, connected);