ACPI: video: output switch sysfs support

Requires CONFIG_VIDEO_OUTPUT_CONTROL and CONFIG_ACPI_VIDEO.

After loading output.ko and video.ko, you would have
/sys/class/video_output and several device acpi_videoNum there.

For example, I got acpi_video0, acpi_video1,acpi_video2,and acpi_video3
under /sys/class/video_output on my T40.
I can query the status of  output device0 by running " cat
/sys/class/video_output/acpi_video0
" The return value is defined in ACPI SPEC B.5.5 _DCS(Return the
Status of Output Device).  Also you can turn off video1 and turn on
video0  by " echo 0 > acpi_video1; echo 0x80000000 > acpi_video0".
Please reference ACPI SPEC  B.5.7 _DSS for the parameter definition.

Please note that it may or may NOT works purely depending on if
your vendor providing correct ACPI video extension support in bios.
the driver output.ko and video.ko just works like a interface to
invoke BIOS.

Signed-off-by: Luming Yu <Luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 1132ba5ff391..6c8ffe6757e1 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -11,6 +11,13 @@ config VGASTATE
        tristate
        default n
 
+config VIDEO_OUTPUT_CONTROL
+        tristate "Lowlevel video output switch controls"
+        default m
+        help
+          This framework adds support for low-level control of the video 
+          output switch.
+
 config FB
         tristate "Support for frame buffer devices"
         ---help---
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index a916c204274f..08b7c26a5734 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -119,3 +119,6 @@ obj-$(CONFIG_FB_OF)               += offb.o
 
 # the test framebuffer is last
 obj-$(CONFIG_FB_VIRTUAL)          += vfb.o
+
+#video output switch sysfs driver
+obj-$(CONFIG_VIDEO_OUTPUT_CONTROL) += output.o