ACPI: Ignore _BQC object when registering backlight device
According to acpi spec , the objectes of _BCL and _BCM are required if
integrated LCD is present and supports brightness level and the _BQC is
the optional object. So the _BQC object will be ignored when the backlight
device is registered.
At the same time when there is no _BQC object, the current brightness will be
set to the maximum.
http://bugzilla.kernel.org/show_bug.cgi?id=10206
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 64c8893..e32b6c1 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -741,7 +741,7 @@
max_level = acpi_video_init_brightness(device);
- if (device->cap._BCL && device->cap._BCM && device->cap._BQC && max_level > 0){
+ if (device->cap._BCL && device->cap._BCM && max_level > 0) {
int result;
static int count = 0;
char *name;
@@ -753,7 +753,17 @@
device->backlight = backlight_device_register(name,
NULL, device, &acpi_backlight_ops);
device->backlight->props.max_brightness = device->brightness->count-3;
- device->backlight->props.brightness = acpi_video_get_brightness(device->backlight);
+ /*
+ * If there exists the _BQC object, the _BQC object will be
+ * called to get the current backlight brightness. Otherwise
+ * the brightness will be set to the maximum.
+ */
+ if (device->cap._BQC)
+ device->backlight->props.brightness =
+ acpi_video_get_brightness(device->backlight);
+ else
+ device->backlight->props.brightness =
+ device->backlight->props.max_brightness;
backlight_update_status(device->backlight);
kfree(name);
