ACPI / video: Add disable_native_backlight quirk for Dell XPS15 L521X

The L521X variant of the Dell XPS15 has integrated nvidia graphics, and
backlight control does not work properly when using the native interfaces.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1163574
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index c72e79d2c5..032db45 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -522,6 +522,16 @@
 		DMI_MATCH(DMI_PRODUCT_NAME, "370R4E/370R4V/370R5E/3570RE/370R5V"),
 		},
 	},
+
+	{
+	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */
+	 .callback = video_disable_native_backlight,
+	 .ident = "Dell XPS15 L521X",
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
+		},
+	},
 	{}
 };