有一个大部分显示器都有, 但是很少人知道的功能: 显示数据通道命令接口 (Display Data Channel Command Interface, DDC/CI) (窝也是刚知道)
这个功能有什么用呢 ? 可以用软件 (主机) 去控制显示器的多种工作参数, 比如亮度, 对比度, 音量, 色温, 输入源等. 大部分使用显示器菜单 (OSD) 可以设置的参数, 通过 DDC/CI 都可以, 再也不用费劲去按显示器上手感超差的按键了 ! (误
本文对 4 台显示设备进行了实际测试, 并对一些控制功能进行了说明.
主要参考资料:
Backlight - ArchWiki https://wiki.archlinux.org/title/Backlight ddcutil: Control monitor settings using DDC/CI and USB https://www.ddcutil.com/ https://github.com/rockowitz/ddcutil ddccontrol: DDCcontrol is a software used to control monitor parameters, like brightness, contrast, RGB color levels and others. https://github.com/ddccontrol/ddccontrol
目录
0 工作原理 (I2C) 1 软件安装 (ArchLinux)
1.1 常用命令 2 显示器: 飞利浦 275M8RZ (27 英寸, 2021 年生产)
2.1 ddcutil 检测 2.2 操作记录 2.3 部分 VCP 说明 3 显示器: HKC T4000 (24 英寸, 2013 年生产)
3.1 ddcutil 检测 3.2 操作记录 3.3 部分 VCP 说明 4 (不支持) 小米电视 A43 pro (43 英寸, 2023 年生产) 5 显示器: (新买不久) (杂牌) (23.6 英寸, 2022 年生产)
5.1 ddcutil 检测 5.2 操作记录 5.3 部分 VCP 说明 6 总结与展望
0 工作原理 (I2C)
主机的显卡和显示器之间, 通过 I2C 总线通信 (DP, HDMI, DVI, VGA 都有). 在这个过程中, 主机不仅可以获取显示器的信息 (分辨率, 刷新率, 显示器名称等), 也可以向显示器发送命令, 这就是 DDC/CI.
具体使用的协议叫做 显示器控制命令集 (Monitor Control Command Set, MCCS), 其中的每一项功能叫做 虚拟控制面板 (Virtual Control Panel, VCP).
1 软件安装 (ArchLinux)
此处以 ArchLinux 举例, 各种操作系统应该都支持.
(1) 安装 ddcutil: > sudo pacman -S ddcutil
(2) 将自己加入 i2c 用户组: > sudo gpasswd -a s20 i2c
此处用户名 s20 需要替换成自己的. (3) 重启.
1.1 常用命令
查看命令帮助信息: > ddcutil --help
查看连接的显示器: > ddcutil detect
查询显示器支持的功能: > ddcutil capabilities
获取某个 VCP 的当前数值: > ddcutil getvcp 10
比如此处使用 10 (亮度). 设置某个 VCP 的数值: > ddcutil setvcp 10 30
比如此处把亮度设为 30. 获取所有 VCP 的当前数值, 比如:
> ddcutil getvcp scan
VCP code 0x02 (New control value ): One or more new control values have been saved (0x02)
VCP code 0x0b (Color temperature increment ): 100 degree(s) Kelvin
VCP code 0x0c (Color temperature request ): 3000 + 70 * (feature 0B color temp increment) degree(s) Kelvin
VCP code 0x10 (Brightness ): current value = 30, max value = 100
VCP code 0x12 (Contrast ): current value = 40, max value = 100
VCP code 0x14 (Select color preset ): 6500 K (0x05), Tolerance: Unspecified (0x00)
VCP code 0x16 (Video gain: Red ): current value = 100, max value = 100
VCP code 0x18 (Video gain: Green ): current value = 100, max value = 100
VCP code 0x1a (Video gain: Blue ): current value = 100, max value = 100
VCP code 0x1e (Auto setup ): Auto setup not active (sl=0x00)
VCP code 0x20 (Horizontal Position (Phase) ): current value = 50, max value = 100
VCP code 0x30 (Vertical Position (Phase) ): current value = 50, max value = 100
VCP code 0x52 (Active control ): Value: 0x32
VCP code 0x54 (Performance Preservation ): mh=0x00, ml=0x01, sh=0x00, sl=0x01
VCP code 0x60 (Input Source ): HDMI-2 (sl=0x12)
VCP code 0x62 (Audio speaker volume ): Volume level: 30 (00x1e)
VCP code 0x6c (Video black level: Red ): current value = 512, max value = 100
VCP code 0x6e (Video black level: Green ): current value = 512, max value = 100
VCP code 0x70 (Video black level: Blue ): current value = 512, max value = 100
VCP code 0x72 (Gamma ): 0x0078 - Invalid sl value. sl=0x78, sh=0x00
VCP code 0x7e (Trapezoid ): Maximum retries exceeded
VCP code 0x86 (Display Scaling ): No scaling (sl=0x01)
VCP code 0x87 (Sharpness ): current value = 5, max value = 10
VCP code 0x8d (Audio mute/Screen blank ): Unmute the audio (sl=0x02), Invalid value (sh=0x00)
VCP code 0xac (Horizontal frequency ): 1 hz
VCP code 0xae (Vertical frequency ): 60.00 hz
VCP code 0xb2 (Flat panel sub-pixel layout ): Red/Green/Blue vertical stripe (sl=0x01)
VCP code 0xb6 (Display technology type ): LCD (active matrix) (sl=0x03)
VCP code 0xc6 (Application enable key ): 0x005a
VCP code 0xc8 (Display controller type ): Mfg: RealTek (sl=0x09), controller number: mh=0x00, ml=0x00, sh=0x00
VCP code 0xc9 (Display firmware level ): 0.1
VCP code 0xca (OSD/Button Control ): OSD disabled, button events enabled (sl=0x01), Host control of power unsupported (sh=0x00)
VCP code 0xcc (OSD Language ): Chinese (simplified / Kantai) (sl=0x0d)
VCP code 0xd6 (Power mode ): DPM: On, DPMS: Off (sl=0x01)
VCP code 0xdf (VCP Version ): 2.2
VCP code 0xe6 (Manufacturer Specific ): mh=0x00, ml=0x00, sh=0x00, sl=0x00
VCP code 0xe9 (Manufacturer Specific ): mh=0x00, ml=0x02, sh=0x00, sl=0x00
VCP code 0xfe (Manufacturer Specific ): Maximum retries exceeded
2 显示器: 飞利浦 275M8RZ (27 英寸, 2021 年生产)
在此说一下这个型号 (275M8RZ) 显示器的一些小知识:
(显示器下方的 4 个按键, 从左至右依次编号为 1 2 3 4, 比如 4 是 OK/菜单 键, 5 是电源开关)
屏幕控制锁定 在这个状态下, 显示器是无法进行设置的, 按显示器的按键只会在屏幕上显示 屏幕控制锁定. 解锁方式:
(1) 关闭显示器 (按 5)(2) 按住 4 不松, 开机 (按 5) 打开/关闭 DDC/CI 在正常显示状态下, 同时按住 1 和 4 不松, 保持一会儿.
屏幕显示 DDC/CI 关闭: 表示已经关闭此功能. 屏幕显示 DDC/CI 开启: 表示已经开启此功能 (默认).
2.1 ddcutil 检测
> ddcutil detect
Display 1
I2C bus: /dev/i2c-10
DRM connector: card2-HDMI-A-1
EDID synopsis:
Mfg id: PHL - Philips Consumer Electronics Company
Model: PHL 275M8RZ
Product code: 49702 (0xc226)
Serial number:
Binary serial number: 1567 (0x0000061f)
Manufacture year: 2021, Week: 9
VCP version: 2.2
成功检测到了显示器, 通过 HDMI 连接, 然后是显示器名称和型号信息. 生产日期 2021 年第 9 周, 支持的 VCP 版本 2.2.
> ddcutil capabilities
Model: 275M8RZ
MCCS version: 2.2
Commands:
Op Code: 01 (VCP Request)
Op Code: 02 (VCP Response)
Op Code: 03 (VCP Set)
Op Code: 07 (Timing Request)
Op Code: 0C (Save Settings)
Op Code: E3 (Capabilities Reply)
Op Code: F3 (Capabilities Request)
VCP Features:
Feature: 02 (New control value)
Feature: 04 (Restore factory defaults)
Feature: 05 (Restore factory brightness/contrast defaults)
Feature: 08 (Restore color defaults)
Feature: 0B (Color temperature increment)
Feature: 0C (Color temperature request)
Feature: 10 (Brightness)
Feature: 12 (Contrast)
Feature: 14 (Select color preset)
Values:
01: sRGB
04: 5000 K
05: 6500 K
06: 7500 K
07: 8200 K
08: 9300 K
0a: 11500 K
0b: User 1
Feature: 16 (Video gain: Red)
Feature: 18 (Video gain: Green)
Feature: 1A (Video gain: Blue)
Feature: 52 (Active control)
Feature: 54 (Performance Preservation)
Values: 00 01 (interpretation unavailable)
Feature: 60 (Input Source)
Values:
11: HDMI-1
12: HDMI-2
0f: DisplayPort-1
Feature: 62 (Audio speaker volume)
Values: 00 01 (interpretation unavailable)
Feature: 6C (Video black level: Red)
Feature: 6E (Video black level: Green)
Feature: 70 (Video black level: Blue)
Feature: 72 (Gamma)
Specific presets of absolute adjustment supported (0xfb)
Absolute tolerance: +/- 5% (=0x05)
Native gamma: 2.20 (0x78)
Specific presets: 1.80 (0x50), 2.00 (0x64), 2.20 (0x78), 2.40 (0x8c), 2.60 (0xa0)
Feature: 86 (Display Scaling)
Values:
01: No scaling
02: Max image, no aspect ration distortion
08: Linear expansion (compression) on h and v axes
Feature: 87 (Sharpness)
Feature: 8D (Audio mute/Screen blank)
Values: 00 01 (interpretation unavailable)
Feature: AC (Horizontal frequency)
Feature: AE (Vertical frequency)
Feature: B2 (Flat panel sub-pixel layout)
Feature: B6 (Display technology type)
Feature: C0 (Display usage time)
Feature: C6 (Application enable key)
Feature: C8 (Display controller type)
Feature: CA (OSD/Button Control)
Values:
01: OSD disabled, button events enabled
02: OSD enabled, button events enabled
Feature: CC (OSD Language)
Values:
01: Chinese (traditional, Hantai)
02: English
03: French
04: German
05: Italian
06: Japanese
07: Korean
08: Portuguese (Portugal)
09: Russian
0a: Spanish
0b: Swedish
0c: Turkish
0d: Chinese (simplified / Kantai)
0e: Portuguese (Brazil)
12: Czech
14: Dutch
16: Finnish
17: Greek
1a: Hungarian
1e: Polish
24: Ukranian
Feature: D6 (Power mode)
Values:
01: DPM: On, DPMS: Off
04: DPM: Off, DPMS: Off
05: Write only value to turn off display
Feature: DC (Display Mode)
Values:
00: Standard/Default mode
01: Productivity
02: Mixed
03: Movie
05: Games
08: Standard/Default mode with intermediate power consumption
Feature: DF (VCP Version)
Feature: E9 (Manufacturer specific feature)
Values: 00 02 (interpretation unavailable)
Feature: EB (Manufacturer specific feature)
Values: 00 01 02 03 (interpretation unavailable)
Feature: F0 (Manufacturer specific feature)
Values: 00 01 (interpretation unavailable)
Feature: FD (Manufacturer specific feature)
Feature: FF (Manufacturer specific feature)
>
显示器型号 275M8RZ, MCCS 版本 2.2, 然后是支持的 VCP 功能列表.
可以看到, 对于大牌显示器, 支持的功能还是比较多的 (后面会详细介绍).
2.2 操作记录
> ddcutil getvcp 02
VCP code 0x02 (New control value ): One or more new control values have been saved (0x02)
> ddcutil getvcp 04
Feature 04 (Restore factory defaults) is not readable
> ddcutil getvcp 05
Feature 05 (Restore factory brightness/contrast defaults) is not readable
> ddcutil getvcp 08
Feature 08 (Restore color defaults) is not readable
> ddcutil getvcp 0b
VCP code 0x0b (Color temperature increment ): 100 degree(s) Kelvin
> ddcutil getvcp 0c
VCP code 0x0c (Color temperature request ): 3000 + 70 * (feature 0B color temp increment) degree(s) Kelvin
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 30, max value = 100
> ddcutil setvcp 10 80
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 80, max value = 100
> ddcutil setvcp 10 30
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 30, max value = 100
> ddcutil getvcp 12
VCP code 0x12 (Contrast ): current value = 40, max value = 100
> ddcutil getvcp 14
VCP code 0x14 (Select color preset ): 6500 K (0x05), Tolerance: Unspecified (0x00)
> ddcutil getvcp 16
VCP code 0x16 (Video gain: Red ): current value = 100, max value = 100
> ddcutil getvcp 18
VCP code 0x18 (Video gain: Green ): current value = 100, max value = 100
> ddcutil getvcp 1a
VCP code 0x1a (Video gain: Blue ): current value = 100, max value = 100
> ddcutil getvcp 52
VCP code 0x52 (Active control ): Value: 0x02
> ddcutil getvcp 54
VCP code 0x54 (Performance Preservation ): mh=0x00, ml=0x01, sh=0x00, sl=0x01
> ddcutil getvcp 60
VCP code 0x60 (Input Source ): HDMI-2 (sl=0x12)
> ddcutil getvcp 62
VCP code 0x62 (Audio speaker volume ): Volume level: 30 (00x1e)
> ddcutil getvcp 6c
VCP code 0x6c (Video black level: Red ): current value = 512, max value = 100
> ddcutil getvcp 6e
VCP code 0x6e (Video black level: Green ): current value = 512, max value = 100
> ddcutil getvcp 70
VCP code 0x70 (Video black level: Blue ): current value = 512, max value = 100
> ddcutil getvcp 72
VCP code 0x72 (Gamma ): 0x0078 - Invalid sl value. sl=0x78, sh=0x00
> ddcutil getvcp 86
VCP code 0x86 (Display Scaling ): No scaling (sl=0x01)
> ddcutil getvcp 87
VCP code 0x87 (Sharpness ): current value = 5, max value = 10
> ddcutil getvcp 8d
VCP code 0x8d (Audio mute/Screen blank ): Unmute the audio (sl=0x02), Invalid value (sh=0x00)
> ddcutil getvcp ac
VCP code 0xac (Horizontal frequency ): 1 hz
> ddcutil getvcp ae
VCP code 0xae (Vertical frequency ): 60.00 hz
> ddcutil getvcp b2
VCP code 0xb2 (Flat panel sub-pixel layout ): Red/Green/Blue vertical stripe (sl=0x01)
> ddcutil getvcp b6
VCP code 0xb6 (Display technology type ): LCD (active matrix) (sl=0x03)
> ddcutil getvcp c0
VCP code 0xc0 (Display usage time ): Unsupported feature code
> ddcutil getvcp c6
VCP code 0xc6 (Application enable key ): 0x005a
> ddcutil getvcp c8
VCP code 0xc8 (Display controller type ): Mfg: RealTek (sl=0x09), controller number: mh=0x00, ml=0x00, sh=0x00
> ddcutil getvcp ca
VCP code 0xca (OSD/Button Control ): OSD disabled, button events enabled (sl=0x01), Host control of power unsupported (sh=0x00)
> ddcutil getvcp cc
VCP code 0xcc (OSD Language ): Chinese (simplified / Kantai) (sl=0x0d)
> ddcutil getvcp d6
VCP code 0xd6 (Power mode ): DPM: On, DPMS: Off (sl=0x01)
> ddcutil getvcp dc
VCP code 0xdc (Display Mode ): Unsupported feature code
> ddcutil getvcp df
VCP code 0xdf (VCP Version ): 2.2
> ddcutil getvcp e9
VCP code 0xe9 (Manufacturer Specific ): mh=0x00, ml=0x02, sh=0x00, sl=0x00
> ddcutil getvcp eb
VCP code 0xeb (Manufacturer Specific ): Unsupported feature code
> ddcutil getvcp f0
VCP code 0xf0 (Manufacturer Specific ): Unsupported feature code
> ddcutil getvcp fd
VCP code 0xfd (Manufacturer Specific ): Unsupported feature code
> ddcutil getvcp ff
VCP code 0xff (Manufacturer Specific ): Unsupported feature code
>
2.3 部分 VCP 说明
此处对一些 VCP 功能进行说明.
VCP 0b 色温增量 > ddcutil getvcp 0b
VCP code 0x0b (Color temperature increment ): 100 degree(s) Kelvin
此处值为 100 开尔文 (K). VCP 0c 色温请求 > ddcutil getvcp 0c
VCP code 0x0c (Color temperature request ): 3000 + 70 * (feature 0B color temp increment) degree(s) Kelvin
公式: 3000 + 70 * 100 K VCP 10 亮度 > ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 30, max value = 100
> ddcutil setvcp 10 80
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 80, max value = 100
这是一个很常用的重要功能. 对于液晶 (LCD) 显示器来说, 亮度是直接控制背光灯的亮度. 此处开始时亮度是 30, 然后修改为 80. VCP 12 对比度 > ddcutil getvcp 12
VCP code 0x12 (Contrast ): current value = 40, max value = 100
当前值 40, 最大值 100. VCP 14 选择颜色预设 > ddcutil getvcp 14
VCP code 0x14 (Select color preset ): 6500 K (0x05), Tolerance: Unspecified (0x00)
参考之前的说明: Feature: 14 (Select color preset)
Values:
01: sRGB
04: 5000 K
05: 6500 K
06: 7500 K
07: 8200 K
08: 9300 K
0a: 11500 K
0b: User 1
VCP 16 视频增益: 红 > ddcutil getvcp 16
VCP code 0x16 (Video gain: Red ): current value = 100, max value = 100
VCP 18 视频增益: 绿 > ddcutil getvcp 18
VCP code 0x18 (Video gain: Green ): current value = 100, max value = 100
VCP 1a 视频增益: 蓝 > ddcutil getvcp 1a
VCP code 0x1a (Video gain: Blue ): current value = 100, max value = 100
VCP 52 活动控制 > ddcutil getvcp 52
VCP code 0x52 (Active control ): Value: 0x02
VCP 54 性能保持 > ddcutil getvcp 54
VCP code 0x54 (Performance Preservation ): mh=0x00, ml=0x01, sh=0x00, sl=0x01
VCP 60 输入源 > ddcutil getvcp 60
VCP code 0x60 (Input Source ): HDMI-2 (sl=0x12)
参考之前的说明: Feature: 60 (Input Source)
Values:
11: HDMI-1
12: HDMI-2
0f: DisplayPort-1
这个显示器有 3 个输入接口: DP, HDMI-1, HDMI-2, 目前使用的是 HDMI-2. VCP 62 音量 > ddcutil getvcp 62
VCP code 0x62 (Audio speaker volume ): Volume level: 30 (00x1e)
这个显示器没有内置喇叭, 但是有一个 3.5mm 接口可以插音箱或耳机. 此处的音量是 30. VCP 6c 视频黑级: 红 > ddcutil getvcp 6c
VCP code 0x6c (Video black level: Red ): current value = 512, max value = 100
VCP 6e 视频黑级: 绿 > ddcutil getvcp 6e
VCP code 0x6e (Video black level: Green ): current value = 512, max value = 100
VCP 70 视频黑级: 蓝 > ddcutil getvcp 70
VCP code 0x70 (Video black level: Blue ): current value = 512, max value = 100
VCP 72 伽马 > ddcutil getvcp 72
VCP code 0x72 (Gamma ): 0x0078 - Invalid sl value. sl=0x78, sh=0x00
参考之前的说明: Feature: 72 (Gamma)
Specific presets of absolute adjustment supported (0xfb)
Absolute tolerance: +/- 5% (=0x05)
Native gamma: 2.20 (0x78)
Specific presets: 1.80 (0x50), 2.00 (0x64), 2.20 (0x78), 2.40 (0x8c), 2.60 (0xa0)
VCP 86 显示缩放 > ddcutil getvcp 86
VCP code 0x86 (Display Scaling ): No scaling (sl=0x01)
参考之前的说明: Feature: 86 (Display Scaling)
Values:
01: No scaling
02: Max image, no aspect ration distortion
08: Linear expansion (compression) on h and v axes
01: 无缩放 02: 保持比例, 放大到全屏 08: 拉伸到全屏 (无视画面的原始比例) VCP 87 锐度 > ddcutil getvcp 87
VCP code 0x87 (Sharpness ): current value = 5, max value = 10
VCP 8d 静音 > ddcutil getvcp 8d
VCP code 0x8d (Audio mute/Screen blank ): Unmute the audio (sl=0x02), Invalid value (sh=0x00)
当前没有静音. VCP ac 水平扫描频率 > ddcutil getvcp ac
VCP code 0xac (Horizontal frequency ): 1 hz
这个随便看看就好, 用处不大. VCP ae 垂直扫描频率 > ddcutil getvcp ae
VCP code 0xae (Vertical frequency ): 60.00 hz
这个就是通常说的显示器刷新率. VCP b2 平板子像素布局 > ddcutil getvcp b2
VCP code 0xb2 (Flat panel sub-pixel layout ): Red/Green/Blue vertical stripe (sl=0x01)
RGB 垂直条带. VCP b6 显示技术类型 > ddcutil getvcp b6
VCP code 0xb6 (Display technology type ): LCD (active matrix) (sl=0x03)
LCD 表示液晶. VCP c6 应用启用键 > ddcutil getvcp c6
VCP code 0xc6 (Application enable key ): 0x005a
(这个干嘛的窝也不懂, 呜 ~ ) VCP c8 显示控制器类型 > ddcutil getvcp c8
VCP code 0xc8 (Display controller type ): Mfg: RealTek (sl=0x09), controller number: mh=0x00, ml=0x00, sh=0x00
这个应该是显示器用的哪种芯片. VCP ca 显示器菜单/按键控制 > ddcutil getvcp ca
VCP code 0xca (OSD/Button Control ): OSD disabled, button events enabled (sl=0x01), Host control of power unsupported (sh=0x00)
参考之前的说明: Feature: CA (OSD/Button Control)
Values:
01: OSD disabled, button events enabled
02: OSD enabled, button events enabled
VCP cc 显示器菜单语言 > ddcutil getvcp cc
VCP code 0xcc (OSD Language ): Chinese (simplified / Kantai) (sl=0x0d)
参考之前的说明: Feature: CC (OSD Language)
Values:
01: Chinese (traditional, Hantai)
02: English
03: French
04: German
05: Italian
06: Japanese
07: Korean
08: Portuguese (Portugal)
09: Russian
0a: Spanish
0b: Swedish
0c: Turkish
0d: Chinese (simplified / Kantai)
0e: Portuguese (Brazil)
12: Czech
14: Dutch
16: Finnish
17: Greek
1a: Hungarian
1e: Polish
24: Ukranian
这个显示器支持的界面语言还挺多的. VCP d6 电源模式 > ddcutil getvcp d6
VCP code 0xd6 (Power mode ): DPM: On, DPMS: Off (sl=0x01)
参考之前的说明: Feature: D6 (Power mode)
Values:
01: DPM: On, DPMS: Off
04: DPM: Off, DPMS: Off
05: Write only value to turn off display
这个可用于控制显示器关机. VCP df VCP 版本 > ddcutil getvcp df
VCP code 0xdf (VCP Version ): 2.2
VCP 版本 2.2.
可以看到, 这个显示器支持的功能还是挺多的.
3 显示器: HKC T4000 (24 英寸, 2013 年生产)
注意, 这个是 10 年前的显示器, 至今仍然正常工作.
3.1 ddcutil 检测
> ddcutil detect
Display 1
I2C bus: /dev/i2c-10
DRM connector: card2-HDMI-A-1
EDID synopsis:
Mfg id: HKC - UNK
Model: T4000+HDMI
Product code: 9216 (0x2400)
Serial number: 0000000000001
Binary serial number: 0 (0x00000000)
Manufacture year: 2013, Week: 33
VCP version: 2.1
成功检测到了显示器, 通过 HDMI 连接. 生产日期 2013 年第 33 周, 支持的 VCP 版本 2.1.
> ddcutil capabilities
Model: FALCON
MCCS version: 2.0
Commands:
Op Code: 01 (VCP Request)
Op Code: 02 (VCP Response)
Op Code: 03 (VCP Set)
Op Code: 07 (Timing Request)
Op Code: 0C (Save Settings)
Op Code: 4E (Unrecognized operation code)
Op Code: F3 (Capabilities Request)
Op Code: E3 (Capabilities Reply)
VCP Features:
Feature: 02 (New control value)
Feature: 04 (Restore factory defaults)
Feature: 05 (Restore factory brightness/contrast defaults)
Feature: 08 (Restore color defaults)
Feature: 0B (Color temperature increment)
Feature: 0C (Color temperature request)
Feature: 10 (Brightness)
Feature: 12 (Contrast)
Feature: 14 (Select color preset)
Values:
01: sRGB
04: 5000 K
05: 6500 K
06: 7500 K
07: 8200 K
08: 9300 K
0a: 11500 K
0b: User 1
Feature: 16 (Video gain: Red)
Feature: 18 (Video gain: Green)
Feature: 1A (Video gain: Blue)
Feature: 6C (Video black level: Red)
Feature: 6E (Video black level: Green)
Feature: 70 (Video black level: Blue)
Feature: AC (Horizontal frequency)
Feature: AE (Vertical frequency)
Feature: B6 (Display technology type)
Feature: C0 (Display usage time)
Feature: C6 (Application enable key)
Feature: C8 (Display controller type)
Feature: C9 (Display firmware level)
Feature: CA (OSD)
Feature: CC (OSD Language)
Values:
00: Reserved value, must be ignored
02: English
03: French
04: German
05: Italian
08: Portuguese (Portugal)
09: Russian
0a: Spanish
0d: Chinese (simplified / Kantai)
Feature: D6 (Power mode)
Values:
01: DPM: On, DPMS: Off
04: DPM: Off, DPMS: Off
Feature: DC (Display Mode)
Values:
00: Standard/Default mode
01: Productivity
02: Mixed
03: Movie
04: User defined
Feature: DF (VCP Version)
Feature: 60 (Input Source)
Values:
01: VGA-1
03: DVI-1
Feature: 62 (Audio speaker volume)
Feature: 8D (Audio Mute)
Feature: FF (Manufacturer specific feature)
Feature: 39 (Vertical Convergence M/G)
Feature: 32 (Vertical Size)
Feature: 35 (Unrecognized feature)
>
显示器型号 FALCON, MCCS 版本 2.0.
VCP 和 MCCS 版本都比上一个显示器低, 正常, 毕竟 10 年前的老显示器. 支持的 VCP 功能也较少.
3.2 操作记录
> ddcutil getvcp 02
VCP code 0x02 (New control value ): One or more new control values have been saved (0x02)
> ddcutil getvcp 04
Feature 04 (Restore factory defaults) is not readable
> ddcutil getvcp 05
Feature 05 (Restore factory brightness/contrast defaults) is not readable
> ddcutil getvcp 08
Feature 08 (Restore color defaults) is not readable
> ddcutil getvcp 0b
VCP code 0x0b (Color temperature increment ): 50 degree(s) Kelvin
> ddcutil getvcp 0c
VCP code 0x0c (Color temperature request ): 3000 + 70 * (feature 0B color temp increment) degree(s) Kelvin
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 70, max value = 100
> ddcutil setvcp 10 30
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 30, max value = 100
> ddcutil setvcp 10 70
> ddcutil getvcp 12
VCP code 0x12 (Contrast ): current value = 50, max value = 100
> ddcutil getvcp 14
VCP code 0x14 (Select color preset ): 5000 K (sl=0x04)
> ddcutil getvcp 16
VCP code 0x16 (Video gain: Red ): current value = 100, max value = 100
> ddcutil getvcp 18
VCP code 0x18 (Video gain: Green ): current value = 100, max value = 100
> ddcutil getvcp 1a
VCP code 0x1a (Video gain: Blue ): current value = 100, max value = 100
> ddcutil getvcp 6c
VCP code 0x6c (Video black level: Red ): current value = 50, max value = 100
> ddcutil getvcp 6e
VCP code 0x6e (Video black level: Green ): current value = 50, max value = 100
> ddcutil getvcp 70
VCP code 0x70 (Video black level: Blue ): current value = 50, max value = 100
> ddcutil getvcp ac
VCP code 0xac (Horizontal frequency ): 8464 hz
> ddcutil getvcp ae
VCP code 0xae (Vertical frequency ): 60.00 hz
> ddcutil getvcp b6
VCP code 0xb6 (Display technology type ): LCD (active matrix) (sl=0x03)
> ddcutil getvcp c0
VCP code 0xc0 (Display usage time ): Usage time (hours) = 7186 (0x001c12) mh=0xff, ml=0xff, sh=0x1c, sl=0x12
> ddcutil getvcp c6
VCP code 0xc6 (Application enable key ): 0x006f
> ddcutil getvcp c8
VCP code 0xc8 (Display controller type ): Mfg: Novatek (sl=0x12), controller number: mh=0xff, ml=0xff, sh=0x00
> ddcutil getvcp c9
VCP code 0xc9 (Display firmware level ): 2.32
> ddcutil getvcp ca
VCP code 0xca (OSD ): OSD Enabled (sl=0x02)
> ddcutil getvcp cc
VCP code 0xcc (OSD Language ): Chinese (simplified / Kantai) (sl=0x0d)
> ddcutil getvcp d6
VCP code 0xd6 (Power mode ): DPM: On, DPMS: Off (sl=0x01)
> ddcutil getvcp dc
VCP code 0xdc (Display Mode ): Mixed (sl=0x02)
> ddcutil getvcp df
VCP code 0xdf (VCP Version ): 2.1
> ddcutil getvcp 60
VCP code 0x60 (Input Source ): DVI-1 (sl=0x03)
> ddcutil getvcp 62
VCP code 0x62 (Audio speaker volume ): current value = 50, max value = 100
> ddcutil getvcp 8d
VCP code 0x8d (Audio Mute ): Unmute the audio (sl=0x02)
> ddcutil getvcp ff
VCP code 0xff (Manufacturer Specific ): mh=0x00, ml=0x01, sh=0x00, sl=0x00
> ddcutil getvcp 39
VCP code 0x39 (Vertical Convergence M/G ): Unsupported feature code
> ddcutil getvcp 32
VCP code 0x32 (Vertical Size ): Unsupported feature code
> ddcutil getvcp 35
VCP code 0x35 (Unknown feature ): Unsupported feature code
>
3.3 部分 VCP 说明
上面介绍过的 VCP 功能基本就不再重复了, 只说一些有意思的.
VCP c0 显示器使用时间 (小时) > ddcutil getvcp c0
VCP code 0xc0 (Display usage time ): Usage time (hours) = 7186 (0x001c12) mh=0xff, ml=0xff, sh=0x1c, sl=0x12
这个显示器已经使用了 7186 小时 (约 300 天). VCP c8 显示控制器类型 > ddcutil getvcp c8
VCP code 0xc8 (Display controller type ): Mfg: Novatek (sl=0x12), controller number: mh=0xff, ml=0xff, sh=0x00
VCP c9 显示器固件版本 > ddcutil getvcp c9
VCP code 0xc9 (Display firmware level ): 2.32
固件版本: 2.32 VCP cc 显示器菜单语言 > ddcutil getvcp cc
VCP code 0xcc (OSD Language ): Chinese (simplified / Kantai) (sl=0x0d)
参考之前的说明: Feature: CC (OSD Language)
Values:
00: Reserved value, must be ignored
02: English
03: French
04: German
05: Italian
08: Portuguese (Portugal)
09: Russian
0a: Spanish
0d: Chinese (simplified / Kantai)
这个显示器支持的界面语言就比较少了. VCP dc 显示模式 > ddcutil getvcp dc
VCP code 0xdc (Display Mode ): Mixed (sl=0x02)
参考之前的说明: Feature: DC (Display Mode)
Values:
00: Standard/Default mode
01: Productivity
02: Mixed
03: Movie
04: User defined
这个就是显示器预设的一些显示模式, 比如标准模式, 电影模式, 用户自定义等. VCP df VCP 版本 > ddcutil getvcp df
VCP code 0xdf (VCP Version ): 2.1
VCP 版本 2.1. VCP 60 输入源 > ddcutil getvcp 60
VCP code 0x60 (Input Source ): DVI-1 (sl=0x03)
参考之前的说明: Feature: 60 (Input Source)
Values:
01: VGA-1
03: DVI-1
这里显示的明显是错的, 这个显示器实际上有 4 个输入接口: DP, HDMI, DVI, VGA. VCP 62 音量 > ddcutil getvcp 62
VCP code 0x62 (Audio speaker volume ): current value = 50, max value = 100
这里也有问题, 这个显示器没有内置喇叭, 也没有音频输出接口. 所以这个音量选项实际上没用.
4 (不支持) 小米电视 A43 pro (43 英寸, 2023 年生产)
小米电视怎么样 ? 试一试吧:
> ddcutil detect
Invalid display
I2C bus: /dev/i2c-10
DRM connector: card2-HDMI-A-1
EDID synopsis:
Mfg id: XMD - UNK
Model: Mi TV
Product code: 234 (0x00ea)
Serial number:
Binary serial number: 1 (0x00000001)
Manufacture year: 2021, Week: 1
DDC communication failed. (getvcp of feature x10 returned Error_Info[ENXIO in ddc_write_read_with_retry, causes: ENXIO])
使用 HDMI 连接小米电视, 获取到了显示器的基本信息, 但是生产日期是错的.
> ddcutil capabilities
Display not found
小米电视不支持 DDC/CI, 有点遗憾.
5 显示器: (新买不久) (杂牌) (23.6 英寸, 2022 年生产)
这个是便宜的杂牌显示器 (全新只要不到 300 元), 只不过显示效果不太好罢了, 但凑合凑合肯定能用.
23.6 英寸, 1920x1080 分辨率 60Hz 刷新率, 还有内置喇叭, HDMI 可以一线同时传输画面和声音, 还是比较香的. 别问窝为啥买这么便宜的显示器 (因为穷)
5.1 ddcutil 检测
> ddcutil detect
Display 1
I2C bus: /dev/i2c-10
DRM connector: card2-HDMI-A-1
EDID synopsis:
Mfg id: GVE - UNK
Model:
Product code: 9491 (0x2513)
Serial number:
Binary serial number: 1 (0x00000001)
Manufacture year: 2022, Week: 29
VCP version: 2.2
成功检测到了显示器, 通过 HDMI 连接. 生产日期 2022 年第 29 周, 支持的 VCP 版本 2.2.
型号 (Model) 直接没有 (果然是杂牌显示器)
> ddcutil capabilities
Model: RTK
MCCS version: 2.2
Commands:
Op Code: 01 (VCP Request)
Op Code: 02 (VCP Response)
Op Code: 03 (VCP Set)
Op Code: 07 (Timing Request)
Op Code: 0C (Save Settings)
Op Code: E3 (Capabilities Reply)
Op Code: F3 (Capabilities Request)
VCP Features:
Feature: 02 (New control value)
Feature: 04 (Restore factory defaults)
Feature: 05 (Restore factory brightness/contrast defaults)
Feature: 06 (Restore factory geometry defaults)
Feature: 08 (Restore color defaults)
Feature: 0B (Color temperature increment)
Feature: 0C (Color temperature request)
Feature: 10 (Brightness)
Feature: 12 (Contrast)
Feature: 14 (Select color preset)
Values:
01: sRGB
02: Display Native
04: 5000 K
05: 6500 K
06: 7500 K
08: 9300 K
0b: User 1
Feature: 16 (Video gain: Red)
Feature: 18 (Video gain: Green)
Feature: 1A (Video gain: Blue)
Feature: 52 (Active control)
Feature: 60 (Input Source)
Values:
01: VGA-1
03: DVI-1
04: DVI-2
0f: DisplayPort-1
10: DisplayPort-2
11: HDMI-1
12: HDMI-2
Feature: 87 (Sharpness)
Feature: AC (Horizontal frequency)
Feature: AE (Vertical frequency)
Feature: B2 (Flat panel sub-pixel layout)
Feature: B6 (Display technology type)
Feature: C6 (Application enable key)
Feature: C8 (Display controller type)
Feature: CA (OSD/Button Control)
Feature: CC (OSD Language)
Values:
01: Chinese (traditional, Hantai)
02: English
03: French
04: German
06: Japanese
0a: Spanish
0d: Chinese (simplified / Kantai)
Feature: D6 (Power mode)
Values:
01: DPM: On, DPMS: Off
04: DPM: Off, DPMS: Off
05: Write only value to turn off display
Feature: DF (VCP Version)
Feature: FD (Manufacturer specific feature)
Feature: FF (Manufacturer specific feature)
>
显示器型号 RTK, MCCS 版本 2.2.
这个显示器支持的 VCP 功能也比较少.
5.2 操作记录
> ddcutil getvcp 02
VCP code 0x02 (New control value ): No new control values (0x01)
> ddcutil getvcp 04
Feature 04 (Restore factory defaults) is not readable
> ddcutil getvcp 05
Feature 05 (Restore factory brightness/contrast defaults) is not readable
> ddcutil getvcp 06
Feature 06 (Restore factory geometry defaults) is not readable
> ddcutil getvcp 08
Feature 08 (Restore color defaults) is not readable
> ddcutil getvcp 0b
VCP code 0x0b (Color temperature increment ): 100 degree(s) Kelvin
> ddcutil getvcp 0c
VCP code 0x0c (Color temperature request ): 3000 + 35 * (feature 0B color temp increment) degree(s) Kelvin
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 41, max value = 100
> ddcutil setvcp 10 10
> ddcutil setvcp 10 0
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 0, max value = 100
> ddcutil setvcp 10 100
> ddcutil getvcp 10
VCP code 0x10 (Brightness ): current value = 100, max value = 100
> ddcutil setvcp 10 40
> ddcutil getvcp 12
VCP code 0x12 (Contrast ): current value = 50, max value = 100
> ddcutil getvcp 14
VCP code 0x14 (Select color preset ): 5000 K (0x04), Tolerance: Unspecified (0x00)
> ddcutil getvcp 16
VCP code 0x16 (Video gain: Red ): current value = 50, max value = 100
> ddcutil getvcp 18
VCP code 0x18 (Video gain: Green ): current value = 50, max value = 100
> ddcutil getvcp 1a
VCP code 0x1a (Video gain: Blue ): current value = 50, max value = 100
> ddcutil getvcp 52
VCP code 0x52 (Active control ): Value: 0x02
> ddcutil getvcp 60
VCP code 0x60 (Input Source ): HDMI-1 (sl=0x11)
> ddcutil getvcp 87
VCP code 0x87 (Sharpness ): current value = 2, max value = 4
> ddcutil getvcp ac
VCP code 0xac (Horizontal frequency ): 2124 hz
> ddcutil getvcp ae
VCP code 0xae (Vertical frequency ): 75.10 hz
> ddcutil getvcp b2
VCP code 0xb2 (Flat panel sub-pixel layout ): Red/Green/Blue vertical stripe (sl=0x01)
> ddcutil getvcp b6
VCP code 0xb6 (Display technology type ): LCD (active matrix) (sl=0x03)
> ddcutil getvcp c6
VCP code 0xc6 (Application enable key ): 0x005a
> ddcutil getvcp c8
VCP code 0xc8 (Display controller type ): Mfg: RealTek (sl=0x09), controller number: mh=0x00, ml=0x00, sh=0x00
> ddcutil getvcp ca
VCP code 0xca (OSD/Button Control ): OSD disabled, button events enabled (sl=0x01), Host control of power unsupported (sh=0x00)
> ddcutil getvcp cc
VCP code 0xcc (OSD Language ): Spanish (sl=0x0a)
> ddcutil getvcp d6
VCP code 0xd6 (Power mode ): DPM: On, DPMS: Off (sl=0x01)
> ddcutil getvcp df
VCP code 0xdf (VCP Version ): 2.2
> ddcutil getvcp fd
VCP code 0xfd (Manufacturer Specific ): Unsupported feature code
> ddcutil getvcp ff
VCP code 0xff (Manufacturer Specific ): Unsupported feature code
>
5.3 部分 VCP 说明
只说一些有意思的 VCP 功能.
VCP 60 输入源 > ddcutil getvcp 60
VCP code 0x60 (Input Source ): HDMI-1 (sl=0x11)
参考之前的说明: Feature: 60 (Input Source)
Values:
01: VGA-1
03: DVI-1
04: DVI-2
0f: DisplayPort-1
10: DisplayPort-2
11: HDMI-1
12: HDMI-2
这里也有问题, 这个显示器只有 2 个输入接口: HDMI, VGA. 这里明显虚标了 (果然是杂牌显示器) VCP c8 显示控制器类型 > ddcutil getvcp c8
VCP code 0xc8 (Display controller type ): Mfg: RealTek (sl=0x09), controller number: mh=0x00, ml=0x00, sh=0x00
VCP cc 显示器菜单语言 > ddcutil getvcp cc
VCP code 0xcc (OSD Language ): Spanish (sl=0x0a)
参考之前的说明: Feature: CC (OSD Language)
Values:
01: Chinese (traditional, Hantai)
02: English
03: French
04: German
06: Japanese
0a: Spanish
0d: Chinese (simplified / Kantai)
这里也是错的, 实际显示器菜单语言是简体中文. (果然是杂牌显示器)
另外还有个问题, 这个显示器有个内置的喇叭, 可以通过 HDMI 传输声音, 但是却没有音量控制的 VCP 功能.
可以看到, 便宜的杂牌显示器的 DDC/CI 功能问题还是比较多的.
6 总结与展望
大部分显示器都支持 DDC/CI 功能, 包括 10 年前的老显示器, 也包括便宜的杂牌显示器. 好的显示器对 DDC/CI 的支持更好一些, 功能也更多一些. 便宜的杂牌显示器问题就比较多了, 但是常用功能还是有的, 基本不影响使用.
有了 DDC/CI, 就可以在此基础上做一些方便的小工具了. 比如显示器按键的手感太差, 按着手疼, 那么可以把常用功能做成软件, 直接用软件调节显示器参数.
也可以做一个自动调节亮度的功能, 可以根据时间进行调节, 比如白天把亮度调高, 晚上把亮度调低. 甚至可以外接一个环境光传感器, 根据光照情况自动调节.
还有很多可能, 上面只是两个小小的栗子.
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