diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 204fe94c7e458c725627422f4eb7bea9a110cf1e..a194f30876c59a9f8d09fca5aec15b40e062546d 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -75,7 +75,8 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
 }
 
 #define FIND_CHILD_MIN_SCORE	1
-#define FIND_CHILD_MAX_SCORE	2
+#define FIND_CHILD_MID_SCORE	2
+#define FIND_CHILD_MAX_SCORE	3
 
 static int match_any(struct acpi_device *adev, void *not_used)
 {
@@ -96,8 +97,17 @@ static int find_child_checks(struct acpi_device *adev, bool check_children)
 		return -ENODEV;
 
 	status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
-	if (status == AE_NOT_FOUND)
+	if (status == AE_NOT_FOUND) {
+		/*
+		 * Special case: backlight device objects without _STA are
+		 * preferred to other objects with the same _ADR value, because
+		 * it is more likely that they are actually useful.
+		 */
+		if (adev->pnp.type.backlight)
+			return FIND_CHILD_MID_SCORE;
+
 		return FIND_CHILD_MIN_SCORE;
+	}
 
 	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED))
 		return -ENODEV;
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 16dcd31d124fe5370f3b2f83bdb8c3a12a3b3760..192d1784e409b49295a322d4068f5637225a1fef 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -432,6 +432,13 @@ static const struct dmi_system_id asus_laptop[] = {
 			DMI_MATCH(DMI_BOARD_NAME, "S5602ZA"),
 		},
 	},
+	{
+		.ident = "Asus ExpertBook B2402CBA",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_BOARD_NAME, "B2402CBA"),
+		},
+	},
 	{
 		.ident = "Asus ExpertBook B2502",
 		.matches = {
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 274344434282ee8e2cc60d91130729270550f536..0c6f06abe3f47f2b77879b0fd051ffb5a043be58 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1370,9 +1370,12 @@ static void acpi_set_pnp_ids(acpi_handle handle, struct acpi_device_pnp *pnp,
 		 * Some devices don't reliably have _HIDs & _CIDs, so add
 		 * synthetic HIDs to make sure drivers can find them.
 		 */
-		if (acpi_is_video_device(handle))
+		if (acpi_is_video_device(handle)) {
 			acpi_add_id(pnp, ACPI_VIDEO_HID);
-		else if (acpi_bay_match(handle))
+			pnp->type.backlight = 1;
+			break;
+		}
+		if (acpi_bay_match(handle))
 			acpi_add_id(pnp, ACPI_BAY_HID);
 		else if (acpi_dock_match(handle))
 			acpi_add_id(pnp, ACPI_DOCK_HID);
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index 1b78c743449282958cbeb2a02157cb1001243538..8a541efc5675663afe636496a03c8f548b53823a 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -50,6 +50,10 @@ static void acpi_video_parse_cmdline(void)
 		acpi_backlight_cmdline = acpi_backlight_video;
 	if (!strcmp("native", acpi_video_backlight_string))
 		acpi_backlight_cmdline = acpi_backlight_native;
+	if (!strcmp("nvidia_wmi_ec", acpi_video_backlight_string))
+		acpi_backlight_cmdline = acpi_backlight_nvidia_wmi_ec;
+	if (!strcmp("apple_gmux", acpi_video_backlight_string))
+		acpi_backlight_cmdline = acpi_backlight_apple_gmux;
 	if (!strcmp("none", acpi_video_backlight_string))
 		acpi_backlight_cmdline = acpi_backlight_none;
 }
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index cd3b75e08ec3fa67d4b4bff40269ca49fa23a20f..e44be31115a6746f079b6a5cc86bbdc7e01cb659 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -230,7 +230,8 @@ struct acpi_pnp_type {
 	u32 hardware_id:1;
 	u32 bus_address:1;
 	u32 platform_id:1;
-	u32 reserved:29;
+	u32 backlight:1;
+	u32 reserved:28;
 };
 
 struct acpi_device_pnp {