From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/power/video_extension.txt | 37 +++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 Documentation/power/video_extension.txt (limited to 'Documentation/power/video_extension.txt') diff --git a/Documentation/power/video_extension.txt b/Documentation/power/video_extension.txt new file mode 100644 index 00000000..b2f9b159 --- /dev/null +++ b/Documentation/power/video_extension.txt @@ -0,0 +1,37 @@ +ACPI video extensions +~~~~~~~~~~~~~~~~~~~~~ + +This driver implement the ACPI Extensions For Display Adapters for +integrated graphics devices on motherboard, as specified in ACPI 2.0 +Specification, Appendix B, allowing to perform some basic control like +defining the video POST device, retrieving EDID information or to +setup a video output, etc. Note that this is an ref. implementation +only. It may or may not work for your integrated video device. + +Interfaces exposed to userland through /proc/acpi/video: + +VGA/info : display the supported video bus device capability like Video ROM, CRT/LCD/TV. +VGA/ROM : Used to get a copy of the display devices' ROM data (up to 4k). +VGA/POST_info : Used to determine what options are implemented. +VGA/POST : Used to get/set POST device. +VGA/DOS : Used to get/set ownership of output switching: + Please refer ACPI spec B.4.1 _DOS +VGA/CRT : CRT output +VGA/LCD : LCD output +VGA/TVO : TV output +VGA/*/brightness : Used to get/set brightness of output device + +Notify event through /proc/acpi/event: + +#define ACPI_VIDEO_NOTIFY_SWITCH 0x80 +#define ACPI_VIDEO_NOTIFY_PROBE 0x81 +#define ACPI_VIDEO_NOTIFY_CYCLE 0x82 +#define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT 0x83 +#define ACPI_VIDEO_NOTIFY_PREV_OUTPUT 0x84 + +#define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS 0x82 +#define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS 0x83 +#define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS 0x84 +#define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS 0x85 +#define ACPI_VIDEO_NOTIFY_DISPLAY_OFF 0x86 + -- cgit v1.2.3