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authorZhang Rui <rui.zhang@intel.com>2012-06-20 09:48:43 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-16 09:04:06 -0700
commit4849c078f07f5eb93eff651d3a32cdd434f0787a (patch)
tree3fe62e4fdce5e8c0bcec87333cd2a9f47c42f387 /drivers/acpi/video.c
parenta00d69ed0676b53e7e5c8d086d47a92f15b91e38 (diff)
ACPI video: Still use ACPI backlight control if _DOS doesn't exist
commit b03738430c7537d5f87948e0b35d8aaf2688c6b4 upstream. This fixes a regression in 3.4-rc1 caused by commit ea9f8856bd6d4ed45885b06a338f7362cd6c60e5 (ACPI video: Harden video bus adding.) Some platforms don't have _DOS control method, but the ACPI backlight still works. We should not invoke _DOS for these platforms. https://bugzilla.kernel.org/show_bug.cgi?id=43168 Cc: Igor Murzov <intergalactic.anonymous@gmail.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/acpi/video.c')
-rw-r--r--drivers/acpi/video.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 66e8f7333e9b..48b5a3cda379 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -558,6 +558,8 @@ acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
union acpi_object arg0 = { ACPI_TYPE_INTEGER };
struct acpi_object_list args = { 1, &arg0 };
+ if (!video->cap._DOS)
+ return 0;
if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
return -EINVAL;