Commit b0373843 authored by Zhang Rui's avatar Zhang Rui Committed by Len Brown

ACPI video: Still use ACPI backlight control if _DOS doesn't exist

This fixes a regression in 3.4-rc1 caused by commit
(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.

Cc: Igor Murzov <>
Signed-off-by: default avatarZhang Rui <>
Signed-off-by: default avatarLen Brown <>
parent 76e10d15
......@@ -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;
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