Index: share/man/man4/acpi_asus.4
===================================================================
--- share/man/man4/acpi_asus.4
+++ share/man/man4/acpi_asus.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd February 8, 2010
+.Dd August 4, 2020
 .Dt ACPI_ASUS 4
 .Os
 .Sh NAME
@@ -49,7 +49,7 @@
 The
 .Nm
 driver provides support for the extra ACPI-controlled gadgets, such as hotkeys
-and leds, found on recent Asus (and Medion) laptops.
+and leds, found on older Asus (and Medion) laptops.
 It allows one to use the
 .Xr sysctl 8
 interface to manipulate the brightness of the LCD panel and the display output
@@ -128,6 +128,8 @@
 .Sh SYSCTL VARIABLES
 The following sysctls are currently implemented:
 .Bl -tag -width indent
+.It Va hw.acpi.asus.kbd_backlight
+Controls the keyboard backlight brightness (-1 for off).
 .It Va hw.acpi.asus.lcd_brightness
 Makes the LCD backlight brighter or dimmer (higher values are brighter).
 .It Va hw.acpi.asus.lcd_backlight
Index: sys/dev/acpi_support/acpi_asus.c
===================================================================
--- sys/dev/acpi_support/acpi_asus.c
+++ sys/dev/acpi_support/acpi_asus.c
@@ -60,6 +60,10 @@
 #define ACPI_ASUS_METHOD_CAMERA	4
 #define ACPI_ASUS_METHOD_CARDRD	5
 #define ACPI_ASUS_METHOD_WLAN	6
+#define ACPI_ASUS_METHOD_KBRN	7
+
+#define KB_BACKLIGHT_LEVEL(lvl) \
+    ((lvl) == -1 ? 0 : (0x80 | (lvl)))
 
 #define _COMPONENT	ACPI_OEM
 ACPI_MODULE_NAME("ASUS")
@@ -79,6 +83,10 @@
 	char	*brn_up;
 	char	*brn_dn;
 
+	char	*kbrn_get;
+	char	*kbrn_set;
+	char	*kbrn_levels;
+
 	char	*lcd_get;
 	char	*lcd_set;
 
@@ -132,6 +140,7 @@
 	struct acpi_asus_led	s_wled;
 
 	int			s_brn;
+	int			s_kbrn;
 	int			s_disp;
 	int			s_lcd;
 	int			s_cam;
@@ -147,6 +156,23 @@
  * as a result of calling the ATK0100 'INIT' method.
  */
 static struct acpi_asus_model acpi_asus_models[] = {
+	{	/*
+		 * G73Jh returns an empty string from 'INIT' and has these
+		 * methods in the DSDT.
+		 */
+		.name		= "",
+		.bled_set	= "BLED",
+		.wled_set	= "WLED",
+		.brn_get	= "GPLV",
+		.brn_set	= "SPLV",
+		.kbrn_get	= "GLKB",
+		.kbrn_set	= "SLKB",
+		.kbrn_levels	= "PWKB",
+		.lcd_get	= "GBTL",
+		.lcd_set	= "SBTL",
+		.disp_get	= "\\ADVG",
+		.disp_set	= "SDSP"
+	},
 	{
 		.name		= "xxN",
 		.mled_set	= "MLED",
@@ -421,6 +447,8 @@
 	{ .name = NULL }
 };
 
+static int	acpi_asus_kbrn_max(struct acpi_asus_softc *sc);
+
 /*
  * Samsung P30/P35 laptops have an Asus ATK0100 gadget interface,
  * but they can't be probed quite the same way as Asus laptops.
@@ -479,6 +507,12 @@
 		.description	= "brightness of the lcd panel",
 		.flag_anybody	= 1
 	},
+	{
+		.name		= "kbd_backlight",
+		.method		= ACPI_ASUS_METHOD_KBRN,
+		.description	= "brightness of the keyboard backlight",
+		.flag_anybody	= 1
+	},
 	{
 		.name		= "video_output",
 		.method		= ACPI_ASUS_METHOD_DISP,
@@ -881,6 +915,34 @@
 	return (0);
 }
 
+static int
+acpi_asus_kbrn_max(struct acpi_asus_softc *sc)
+{
+	ACPI_BUFFER buf;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	if (sc->model->kbrn_levels == NULL)
+		return (-1);
+
+	/*
+	 * kbrn_levels is a lookup table of brightness levels for the
+	 * keyboard backlight.  We only need its length.
+	 */
+	buf.Pointer = NULL;
+	buf.Length = 0;
+	if (AcpiEvaluateObject(sc->handle, sc->model->kbrn_levels, NULL, &buf)
+	    == AE_BUFFER_OVERFLOW)
+		return (buf.Length);
+
+	/*
+	 * If that didn't work we might have the wrong path to the table.
+	 * The SLKB method commonly takes values up to 127, we'll just get
+	 * an error message on the console if we go past the end of the table.
+	 */
+	return (0x7F);
+}
+
 static void
 acpi_asus_led_task(struct acpi_asus_led *led, int pending __unused)
 {
@@ -985,6 +1047,9 @@
 	case ACPI_ASUS_METHOD_BRN:
 		val = sc->s_brn;
 		break;
+	case ACPI_ASUS_METHOD_KBRN:
+		val = sc->s_kbrn;
+		break;
 	case ACPI_ASUS_METHOD_DISP:
 		val = sc->s_disp;
 		break;
@@ -1040,6 +1105,19 @@
 		if (ACPI_SUCCESS(status))
 			sc->s_brn = arg;
 
+		break;
+	case ACPI_ASUS_METHOD_KBRN:
+		/* -1 is off, otherwise an index in the brightness table */
+		if (arg < -1 || arg > acpi_asus_kbrn_max(sc))
+			return (EINVAL);
+
+		if (sc->model->kbrn_set)
+			status = acpi_SetInteger(sc->handle,
+			    sc->model->kbrn_set, KB_BACKLIGHT_LEVEL(arg));
+
+		if (ACPI_SUCCESS(status))
+			sc->s_kbrn = arg;
+
 		break;
 	case ACPI_ASUS_METHOD_DISP:
 		if (arg < 0 || arg > 7)
@@ -1130,6 +1208,14 @@
 			return (TRUE);
 		}
 		return (FALSE);
+	case ACPI_ASUS_METHOD_KBRN:
+		if (sc->model->kbrn_get) {
+			status = acpi_GetInteger(sc->handle,
+			    sc->model->kbrn_get, &sc->s_kbrn);
+			if (ACPI_SUCCESS(status))
+				return (TRUE);
+		}
+		return (FALSE);
 	case ACPI_ASUS_METHOD_DISP:
 		if (sc->model->disp_get) {
 			status = acpi_GetInteger(sc->handle,
@@ -1230,6 +1316,14 @@
 	} else if (notify == 0x87) {
 		acpi_asus_sysctl_set(sc, ACPI_ASUS_METHOD_BRN, sc->s_brn+1);
 		ACPI_VPRINT(sc->dev, acpi_sc, "Brightness increased\n");
+	} else if (notify == 0xC4) {
+		acpi_asus_sysctl_set(sc, ACPI_ASUS_METHOD_KBRN, sc->s_kbrn+1);
+		ACPI_VPRINT(sc->dev, acpi_sc,
+		    "Keyboard backlight brightness increased\n");
+	} else if (notify == 0xC5) {
+		acpi_asus_sysctl_set(sc, ACPI_ASUS_METHOD_KBRN, sc->s_kbrn-1);
+		ACPI_VPRINT(sc->dev, acpi_sc,
+		    "Keyboard backlight brightness decreased\n");
 	} else {
 		/* Notify devd(8) */
 		acpi_UserNotify("ASUS", h, notify);