diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 9922cc46b15c44d75171b38f57518562829586da..cb6066c809ea03dddec42b0871e22a67ef242726 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1030,6 +1030,10 @@ static struct dmi_system_id ec_dmi_table[] __initdata = {
 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
 	{
+	ec_flag_msi, "Clevo W350etq", {
+	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."),
+	DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, NULL},
+	{
 	ec_validate_ecdt, "ASUS hardware", {
 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
 	{
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 826884392e6b4b9df067623cfad758c29ea954a7..fcbda105616eb703b87e50ee88650cd4dde72d78 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -82,9 +82,9 @@ module_param(allow_duplicates, bool, 0644);
  * For Windows 8 systems: used to decide if video module
  * should skip registering backlight interface of its own.
  */
-static int use_native_backlight_param = 1;
+static int use_native_backlight_param = -1;
 module_param_named(use_native_backlight, use_native_backlight_param, int, 0444);
-static bool use_native_backlight_dmi = false;
+static bool use_native_backlight_dmi = true;
 
 static int register_count;
 static struct mutex video_list_lock;
@@ -417,6 +417,12 @@ static int __init video_set_use_native_backlight(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int __init video_disable_native_backlight(const struct dmi_system_id *d)
+{
+	use_native_backlight_dmi = false;
+	return 0;
+}
+
 static struct dmi_system_id video_dmi_table[] __initdata = {
 	/*
 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
@@ -720,6 +726,41 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
 		},
 	},
+
+	/*
+	 * These models have a working acpi_video backlight control, and using
+	 * native backlight causes a regression where backlight does not work
+	 * when userspace is not handling brightness key events. Disable
+	 * native_backlight on these to fix this:
+	 * https://bugzilla.kernel.org/show_bug.cgi?id=81691
+	 */
+	{
+	 .callback = video_disable_native_backlight,
+	 .ident = "ThinkPad T420",
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
+		},
+	},
+	{
+	 .callback = video_disable_native_backlight,
+	 .ident = "ThinkPad T520",
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
+		},
+	},
+
+	/* The native backlight controls do not work on some older machines */
+	{
+	 /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
+	 .callback = video_disable_native_backlight,
+	 .ident = "HP ENVY 15 Notebook",
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
+		},
+	},
 	{}
 };