| From | Greg Kroah-Hartman <> | Subject | [ 075/187] ACPI video: Still use ACPI backlight control if _DOS doesnt exist | Date | Thu, 12 Jul 2012 15:33:51 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
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From: Zhang Rui <rui.zhang@intel.com>
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>
--- drivers/acpi/video.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -558,6 +558,8 @@ acpi_video_bus_DOS(struct acpi_video_bus 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;
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