ACPI / video: Add a disable_native_backlight quirk
Some laptops have a working acpi_video backlight control, and using native
backlight on these causes a regression where backlight control does not work
when userspace is not handling brightness key events. Disable native_backlight
on these to fix this.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=81691
Reported-and-tested-by: Andre Müller <andre.muller@web.de>
Cc: 3.16+ <stable@vger.kernel.org> # 3.16+
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 58bcf7a..dd5c302 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -417,6 +417,12 @@
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 +726,30 @@
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"),
+ },
+ },
{}
};