VESA DDC连接是一个

I2C连接，可用于查询显示器的存在。

请注意以下内容：控制0xe1：/ 1/1 [SAM：电源控制(0 – 关/ 1 – 开)]

# ddcci-tool /dev/i2c-2 -e -c -d

ddcci-tool version 0.03

Reading EDID : 0x50@/dev/i2c-2

Plug and Play ID: SAM00BA

Input type: Analog

Using ddc/ci : 0x37@/dev/i2c-2

Capabilities:

(type(LCD)vcp(04 05 10 12 60(1 3) B0(1 2) B6 C6 C8 C9 D6(1 4) DC(1 2 3 4) DF))

Controls (valid/current/max):

Control 0x04: +/0/1 [Reset Factory Defaults]

Control 0x05: +/0/1 [SAM: Reset Brightness and Contrast]

Control 0x06: +/0/1 [Reset Factory Geometry]

Control 0x08: +/0/1 [Reset Factory Default Color]

Control 0x0e: +/60/120 [SAM: Image Lock Coarse]

Control 0x10: +/0/100 [Brightness]

Control 0x12: +/50/100 [Contrast]

Control 0x16: +/8/16 [Red Video Gain]

Control 0x18: +/8/16 [Green Video Gain]

Control 0x1a: +/8/16 [Blue Video Gain]

Control 0x1e: +/0/2 [SAM: Auto Size Center]

Control 0x20: +/50/100 [Horizontal Position]

Control 0x30: +/25/54 [Vertical Position]

Control 0x3e: +/39/50 [SAM: Image Lock Fine]

Control 0x60: +/1/3 [Input Source Select]

Control 0x62: +/0/100 [Audio Speaker Volume Adjust]

Control 0x6c: +/140/255 [Red Video Black Level]

Control 0x6e: +/127/255 [Green Video Black Level]

Control 0x70: +/121/255 [Blue Video Black Level]

Control 0xb0: +/0/2 [Settings]

Control 0xb6: +/3/8 [???]

Control 0xc6: +/1/1 [???]

Control 0xc8: +/5/16 [???]

Control 0xc9: +/1/0 [???]

Control 0xca: +/2/2 [On Screen Display]

Control 0xcc: +/2/11 [SAM: On Screen Display Language]

Control 0xd6: +/1/4 [SAM: DPMS control (1 - on/4 - stby)]

Control 0xdc: +/4/4 [SAM: MagicBright (1 - text/2 - internet/3 - entertain/4 - custom)]

Control 0xdf: +/512/0 [VCP Version]

Control 0xe0: +/0/2 [SAM: Color preset (0 - normal/1 - warm/2 - cool)]

Control 0xe1: +/1/1 [SAM: Power control (0 - off/1 - on)]

Control 0xe2: +/0/1 [???]

Control 0xed: +/108/255 [SAM: Red Video Black Level]

Control 0xee: +/101/255 [SAM: Green Video Black Level]

Control 0xef: +/103/255 [SAM: Blue Video Black Level]

一个有趣的问题是您的显示器是否返回该数据，如果没有返回，那么它是否在当前关闭的情况下完全响应。