thinkpad-acpi: untangle ACPI/vendor backlight selection
acpi_video_backlight_support() already tells us if ACPI is handling
backlight control through the generic ACPI handle. It is better to just
trust it.
While at it, adjust down a printk priority, and test earlier for
brightness_enable=0.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index f6f8025..1565eefd 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -1024,6 +1024,10 @@
backlight brightness control interface if it detects that the standard
ACPI interface is available in the ThinkPad.
+If you want to use the thinkpad-acpi backlight brightness control
+instead of the generic ACPI video backlight brightness control for some
+reason, you should use the acpi_backlight=vendor kernel parameter.
+
The brightness_enable module parameter can be used to control whether
the LCD brightness control feature will be enabled when available.
brightness_enable=0 forces it to be disabled. brightness_enable=1