From d80fb99fdcd56f4934f11cc44ca016463842dc8b Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Wed, 18 Mar 2009 16:27:14 +0800 Subject: [PATCH] ACPI video: support reversed _BCL method in ACPI video driver 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 Acked-by: Matthew Garrett Acked-by: Thomas Renninger Signed-off-by: Len Brown --- drivers/acpi/video.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 398b3eee37fb..dc84970ce1e9 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; -- 2.20.1