output: Add output class document

Signed-off-by: Luming Yu <Luming.yu@intel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Yu Luming 2006-12-19 12:56:18 -08:00 committed by Len Brown
parent 2dec3ba8d8
commit b03637b886

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Video Output Switcher Control
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2006 luming.yu@intel.com
The output sysfs class driver provides an abstract video output layer that
can be used to hook platform specific methods to enable/disable video output
device through common sysfs interface. For example, on my IBM ThinkPad T42
laptop, The ACPI video driver registered its output devices and read/write
method for 'state' with output sysfs class. The user interface under sysfs is:
linux:/sys/class/video_output # tree .
.
|-- CRT0
| |-- device -> ../../../devices/pci0000:00/0000:00:01.0
| |-- state
| |-- subsystem -> ../../../class/video_output
| `-- uevent
|-- DVI0
| |-- device -> ../../../devices/pci0000:00/0000:00:01.0
| |-- state
| |-- subsystem -> ../../../class/video_output
| `-- uevent
|-- LCD0
| |-- device -> ../../../devices/pci0000:00/0000:00:01.0
| |-- state
| |-- subsystem -> ../../../class/video_output
| `-- uevent
`-- TV0
|-- device -> ../../../devices/pci0000:00/0000:00:01.0
|-- state
|-- subsystem -> ../../../class/video_output
`-- uevent