[PATCH 91/98] ACPI video: support reversed _BCL method in ACPI video driver

Len Brown
2009-03-28T04:33:58Z

From: Zhang Rui <rui.zhang@intel.com>

The brightness levels returned by _BCL package are in a reversed order
on some laptops.
http://bugzilla.kernel.org/show_bug.cgi?id=12037
http://bugzilla.kernel.org/show_bug.cgi?id=12302
http://bugzilla.kernel.org/show_bug.cgi?id=12235

sort the _BCL packge in case it's reversed.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/acpi/video.c | 12 +++++++++---
1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 398b3ee..dc84970 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -170,6 +170,7 @@ struct acpi_video_device_cap {

struct acpi_video_brightness_flags {
u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
+ u8 _BCL_reversed:1; /* _BCL package is in a reversed order*/
};

struct acpi_video_device_brightness {
@@ -744,9 +745,14 @@ acpi_video_init_brightness(struct acpi_video_device *device)
} else if (level_ac_battery > 2)
ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package\n"));

- /* sort all the supported brightness levels */
- sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
- acpi_video_cmp_level, NULL);
+ /* Check if the _BCL package is in a reversed order */
+ if (max_level == br->levels[2]) {
+ br->flags._BCL_reversed = 1;
+ sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
+ acpi_video_cmp_level, NULL);
+ } else if (max_level != br->levels[count - 1])
+ ACPI_ERROR((AE_INFO,
+ "Found unordered _BCL package\n"));

br->count = count;
device->brightness = br;
--
1.6.0.6