[patch 24/26] ACPI: Ignore _BQC object when registering backlight device

Greg KH
2008-10-18T19:05:39Z

[-- Attachment #1: acpi-ignore-_bqc-object-when-registering-backlight-device.patch --]
[-- Type: text/plain, Size: 2043 bytes --]

2.6.26-stable review patch. If anyone has any objections, please let us
know.

------------------
From: Zhao Yakui <yakui.zhao@intel.com>

upstream commmit: c2c789057f075022658b38b498755c29c1ba8055

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>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/acpi/video.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -720,7 +720,7 @@ static void acpi_video_device_find_cap(s

kfree(obj);

- 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;
@@ -732,7 +732,17 @@ static void acpi_video_device_find_cap(s
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);

--