The ThinkPad X201s has a working ACPI video backlight interface and is shipped before Win8; then there is BIOS update that starts to query _OSI("Windows 2012") and that would make our video module stop creating backlight interface and caused problem for the user. Add it to the DMI table to disable native backlight to fix this problem. LINK: https://bugzilla.kernel.org/show_bug.cgi?id=81691 LINK: https://bugzilla.kernel.org/show_bug.cgi?id=51231 Cc: 3.16+ <stable@xxxxxxxxxxxxxxx> # 3.16+ Reported-and-tested-by: Yves-Alexis Perez <corsac@xxxxxxxxxx> Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> --- drivers/acpi/video.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index fcbda105616e..8e7e18567ae6 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -750,6 +750,14 @@ static struct dmi_system_id video_dmi_table[] __initdata = { DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"), }, }, + { + .callback = video_disable_native_backlight, + .ident = "ThinkPad X201s", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), + DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"), + }, + }, /* The native backlight controls do not work on some older machines */ { -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html