Root/Documentation/power/video_extension.txt

1ACPI video extensions
2~~~~~~~~~~~~~~~~~~~~~
3
4This driver implement the ACPI Extensions For Display Adapters for
5integrated graphics devices on motherboard, as specified in ACPI 2.0
6Specification, Appendix B, allowing to perform some basic control like
7defining the video POST device, retrieving EDID information or to
8setup a video output, etc. Note that this is an ref. implementation
9only. It may or may not work for your integrated video device.
10
11Interfaces exposed to userland through /proc/acpi/video:
12
13VGA/info : display the supported video bus device capability like Video ROM, CRT/LCD/TV.
14VGA/ROM : Used to get a copy of the display devices' ROM data (up to 4k).
15VGA/POST_info : Used to determine what options are implemented.
16VGA/POST : Used to get/set POST device.
17VGA/DOS : Used to get/set ownership of output switching:
18    Please refer ACPI spec B.4.1 _DOS
19VGA/CRT : CRT output
20VGA/LCD : LCD output
21VGA/TVO : TV output
22VGA/*/brightness : Used to get/set brightness of output device
23
24Notify event through /proc/acpi/event:
25
26#define ACPI_VIDEO_NOTIFY_SWITCH 0x80
27#define ACPI_VIDEO_NOTIFY_PROBE 0x81
28#define ACPI_VIDEO_NOTIFY_CYCLE 0x82
29#define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT 0x83
30#define ACPI_VIDEO_NOTIFY_PREV_OUTPUT 0x84
31
32#define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS 0x82
33#define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS 0x83
34#define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS 0x84
35#define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS 0x85
36#define ACPI_VIDEO_NOTIFY_DISPLAY_OFF 0x86
37
38

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