tree 2d4500519867b0ff345c3e895d7fdb90739023a7
parent 6b7b284958d47b77d06745b36bc7f36dab769d9b
author Zhang Rui <rui.zhang@intel.com> 1262159963 +0800
committer Len Brown <len.brown@intel.com> 1262223004 -0500

ACPI video: Prune dupe video devices, unless "video.allow_duplicates"

Some buggy BIOS exports multiple ACPI video bus devices for the same
VGA controller, and multiple backlight control methods as well.
This messes up the ACPI video backlight control.

http://bugzilla.kernel.org/show_bug.cgi?id=13577

With this patch applied, only the FIRST ACPI video bus device
under a PCI device node is bind to ACPI video driver by default.

If the first ACPI video bus device doesn't work well, we can use
video.allow_duplicates=1 to go back to the old behavior.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>