Ubuntu Linux下同款USB-C转HDMI适配器DDC/CI通信功能不一致问题求助

阿华AIGC实验室

2026-4-20

大家好，我最近碰到了一个挺棘手的问题，想请社区里的各位大佬帮忙看看：我的Ubuntu笔记本通过USB-C转HDMI扩展坞连接两台外接显示器时，DDC/CI通信完全失效，但直接用HDMI线连接的话一切正常。更奇怪的是，朋友同款的Anker 555扩展坞在他的设备上就能正常使用DDC/CI，难道能不能用全靠运气吗？

设备环境细节

笔记本系统：Ubuntu Linux，内核版本 6.5.0-17-generic
CPU：Intel i5-12500H
GPU驱动：i915
USB-C扩展坞：
- Anker 555 USB-C Hub（8合1）：我自己的这款无法使用DDC，但朋友同款可以正常调节亮度等参数
- Anker 332 USB-C Hub：同样无法使用DDC
外接显示器：2台Dell SE2422HX
- 直接HDMI连接：DDC/CI正常工作
- 通过上述两款扩展坞连接：DDC/CI失效

已做的排查步骤

确认两台显示器都支持DDC/CI（之前用ddcutil成功调节过亮度等参数）
使用ddcutil能正确识别显示器，但用“失效”的扩展坞连接时，会提示DDC communication failed
检查过所有扩展坞，都没有可用的固件更新

`ddcutil detect -verbose` 输出对比（两款Anker 555扩展坞同时连接的情况）

正常工作的显示器（连接朋友的Anker 555）

Display 1
I2C bus:  /dev/i2c-13
DRM connector:                      card0-DP-1
Driver:                             i915
I2C address 0x50 (EDID) responsive: true
Is eDP device:                      false
Is LVDS device:                     false
/sys/bus/i2c/devices/i2c-13/name    AUX USBC1/DDI TC1/PHY TC1
PCI device path:                    /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-1/i2c-13
EDID synopsis:
Mfg id:               DEL - Dell Inc.
Model:                DELL SE2422HX
Product code:         41418  (0xa1ca)
Serial number:        53D5WB3
Binary serial number: 808863825 (0x30364851)
Manufacture year:     2021,  Week: 16
EDID version:         1.3
Extra descriptor:
Video input definition:    0x80 - Digital Input
Supported features:
DPMS standby
DPMS suspend
DPMS active-off
Digital display type: RGB 4:4:4 + YCrCb 4:4:4
Standard sRGB color space: False
White x,y:        0.313, 0.329
Red   x,y:        0.650, 0.333
Green x,y:        0.317, 0.615
Blue  x,y:        0.151, 0.060
Extension blocks: 1
EDID source: I2C
EDID hex dump:
+0          +4          +8          +c            0   4   8   c
+0000   00 ff ff ff ff ff ff 00 10 ac ca a1 51 48 36 30   ............QH60
+0010   10 1f 01 03 80 35 1e 78 ee 96 d5 a6 55 51 9d 26   .....5.x....UQ.&
+0020   0f 50 54 a5 4b 00 71 4f 81 80 a9 c0 d1 c0 01 01   .PT.K.qO........
+0030   01 01 01 01 01 01 02 3a 80 18 71 38 2d 40 58 2c   .......:..q8-@X,
+0040   45 00 0f 28 21 00 00 1e 00 00 00 ff 00 35 33 44   E..(!........53D
+0050   35 57 42 33 0a 20 20 20 20 20 00 00 00 fc 00 44   5WB3.     .....D
+0060   45 4c 4c 20 53 45 32 34 32 32 48 58 00 00 00 fd   ELL SE2422HX....
+0070   00 30 4b 1f 54 12 00 0a 20 20 20 20 20 20 01 0e   .0K.T...      ..
VCP version:         2.1
Controller mfg:      Mstar
Firmware version:    41.2
Monitor returns DDC Null Response for unsupported features: false

无法工作的显示器（连接我的Anker 555）

Invalid display
I2C bus:  /dev/i2c-15
DRM connector:                      card0-DP-3
Driver:                             i915
I2C address 0x50 (EDID) responsive: true
Is eDP device:                      false
Is LVDS device:                     false
/sys/bus/i2c/devices/i2c-15/name    AUX USBC3/DDI TC3/PHY TC3
PCI device path:                    /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-3/i2c-15
EDID synopsis:
Mfg id:               DEL - Dell Inc.
Model:                DELL SE2422HX
Product code:         41418  (0xa1ca)
Serial number:        GHC5WB3
Binary serial number: 808928849 (0x30374651)
Manufacture year:     2021,  Week: 16
EDID version:         1.3
Extra descriptor:
Video input definition:    0x80 - Digital Input
Supported features:
DPMS standby
DPMS suspend
DPMS active-off
Digital display type: RGB 4:4:4 + YCrCb 4:4:4
Standard sRGB color space: False
White x,y:        0.313, 0.329
Red   x,y:        0.650, 0.333
Green x,y:        0.317, 0.615
Blue  x,y:        0.151, 0.060
Extension blocks: 1
EDID source: I2C
EDID hex dump:
+0          +4          +8          +c            0   4   8   c
+0000   00 ff ff ff ff ff ff 00 10 ac ca a1 51 46 37 30   ............QF70
+0010   10 1f 01 03 80 35 1e 78 ee 96 d5 a6 55 51 9d 26   .....5.x....UQ.&
+0020   0f 50 54 a5 4b 00 71 4f 81 80 a9 c0 d1 c0 01 01   .PT.K.qO........
+0030   01 01 01 01 01 01 02 3a 80 18 71 38 2d 40 58 2c   .......:..q8-@X,
+0040   45 00 0f 28 21 00 00 1e 00 00 00 ff 00 47 48 43   E..(!........GHC
+0050   35 57 42 33 0a 20 20 20 20 20 00 00 00 fc 00 44   5WB3.     .....D
+0060   45 4c 4c 20 53 45 32 34 32 32 48 58 00 00 00 fd   ELL SE2422HX....
+0070   00 30 4b 1f 54 12 00 0a 20 20 20 20 20 20 01 e9   .0K.T...      ..
DDC communication failed