Just like the Dell XPS 15 (L521X) the Dell XPS 14 (L421X) needs to use the acpi-video backlight interface rather then the native one for backlight control to work, add a quirk for this. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1272633 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> --- drivers/acpi/video_detect.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index 0d3a384..daaf1c4 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -233,6 +233,15 @@ static const struct dmi_system_id video_detect_dmi_table[] = { }, }, { + /* https://bugzilla.redhat.com/show_bug.cgi?id=1272633 */ + .callback = video_detect_force_video, + .ident = "Dell XPS14 L421X", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"), + }, + }, + { /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */ .callback = video_detect_force_video, .ident = "Dell XPS15 L521X", -- 2.5.0 -- 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