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. https://bugzilla.kernel.org/show_bug.cgi?id=81691 Reported-and-tested-by: Andre Müller <andre.muller@xxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 3.16 Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> --- drivers/acpi/video.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) 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 @@ 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 +726,30 @@ 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"), + }, + }, {} }; -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html