Invalid display with eDP laptop when running ddcutil detect

[Bryan2333]

My OS is Arch Linux with KDE Plasma. I'm using a KDE widget called ddcci-plasmoid, which can be used to adjust the brightness of external monitors. The widget relies on ddcutil.

Recently, I found some error logs from systemd-journald like this

11月 13 11:03:18 Bryan-YOGA14s ddcutil[6958]: busno=6, sleep-multiplier =  2.00. Testing for supported feature 0x10 returned Error_Info[EIO in ddc_write_read_with_retry, causes: EIO]

When I run the command ddcutil detect, I get an error about my laptop eDP display, which seems related to it.

┬─[bryan@Bryan-YOGA14s:~]─[10时55分46秒]
╰─>$ ddcutil detect
Invalid display
   I2C bus:  /dev/i2c-6
   DRM connector:           card1-eDP-1
   EDID synopsis:
      Mfg id:               CSO - California Institute of Technology
      Model:                
      Product code:         5122  (0x1402)
      Serial number:        
      Binary serial number: 0 (0x00000000)
      Manufacture year:     2020,  Week: 0
   DDC communication failed. (getvcp of feature x10 returned Error_Info[EIO in ddc_write_read_with_retry, causes: EIO])
   This is an eDP laptop display. Laptop displays do not support DDC/CI.
   DRM reports the monitor is in a DPMS sleep state (Off).
   DRM reports the monitor is disabled.

Display 1
   I2C bus:  /dev/i2c-8
   DRM connector:           card1-DP-2
   EDID synopsis:
      Mfg id:               PHL - Philips Consumer Electronics Company
      Model:                PHL24E1N5600
      Product code:         49801  (0xc289)
      Serial number:        UK02226014209
      Binary serial number: 14209 (0x00003781)
      Manufacture year:     2022,  Week: 26
   VCP version:         2.2

Here is the file of ddcutil interrogate --verbose
ddcutillog.txt

[rockowitz]

The key message is: "This is an eDP laptop display. Laptop displays do not support DDC/CI ".