sony-laptop: fingers off backlight if video.ko is serving this functionality

Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/misc/sony-laptop.c b/drivers/misc/sony-laptop.c
index 06f07e19dc7..7bcb81002dc 100644
--- a/drivers/misc/sony-laptop.c
+++ b/drivers/misc/sony-laptop.c
@@ -1038,7 +1038,11 @@ static int sony_nc_add(struct acpi_device *device)
                 goto outinput;
         }
 
-        if (ACPI_SUCCESS(acpi_get_handle(sony_nc_acpi_handle, "GBRT", &handle))) {
+        if (!acpi_video_backlight_support()) {
+                printk(KERN_INFO DRV_PFX "Sony: Brightness ignored, must be "
+                       "controlled by ACPI video driver\n");
+        } else if (ACPI_SUCCESS(acpi_get_handle(sony_nc_acpi_handle, "GBRT",
+                                                &handle))) {
                 sony_backlight_device = backlight_device_register("sony", NULL,
                                                                   NULL,
                                                                   &sony_backlight_ops);