From: Zhao Yakui Date: Thu, 17 Jul 2008 02:46:05 +0000 (+0800) Subject: ACPI: Ignore _BQC object when registering backlight device X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c2c789057f075022658b38b498755c29c1ba8055;p=deliverable%2Flinux.git 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 Signed-off-by: Zhang Rui Signed-off-by: Andi Kleen --- diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 64c889331f3b..e32b6c14d928 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -741,7 +741,7 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device) 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 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device) 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);