platform/x86: asus-wmi: Disable OOBE experience on Zenbook S 16

The OOBE experience fades the keyboard backlight in & out continuously,
and make the backlight uncontrollable using its device.

Workaround taken from
https://wiki.archlinux.org/index.php?title=ASUS_Zenbook_UM5606&diff=next&oldid=815547

Signed-off-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Luke D. Jones <luke@ljones.dev>
Link: https://lore.kernel.org/r/20240909223503.1445779-1-bas@basnieuwenhuizen.nl
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

drivers/platform/x86/asus-wmi.c

@@ -1793,6 +1793,16 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
 			goto error;
 	}
 
+	if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_OOBE)) {
+		/*
+		 * Disable OOBE state, so that e.g. the keyboard backlight
+		 * works.
+		 */
+		rv = asus_wmi_set_devstate(ASUS_WMI_DEVID_OOBE, 1, NULL);
+		if (rv)
+			goto error;
+	}
+
 error:
 	if (rv)
 		asus_wmi_led_exit(asus);

include/linux/platform_data/x86/asus-wmi.h

@@ -62,6 +62,7 @@
 #define ASUS_WMI_DEVID_KBD_BACKLIGHT	0x00050021
 #define ASUS_WMI_DEVID_LIGHT_SENSOR	0x00050022 /* ?? */
 #define ASUS_WMI_DEVID_LIGHTBAR		0x00050025
+#define ASUS_WMI_DEVID_OOBE		0x0005002F
 /* This can only be used to disable the screen, not re-enable */
 #define ASUS_WMI_DEVID_SCREENPAD_POWER	0x00050031
 /* Writing a brightness re-enables the screen if disabled */