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