Arch Linux

vavra.7

Member

Registered: 2021-05-22

Posts: 18

Brightness of external displays connected via docking station

Is there some way how to set brightness of external displays that are connected via docking station? I am able to set brightness using ddcutil with command such a "ddcutil setvcp 10 100" but only when the display is connected to my laptop directly. However I am connecting my displays via docking station using evdi-git and displaylink. With this configuration ddcutil is unable to detect my external displays and command "ddcutil detect" returns following:

Unable to open directory /sys/bus/i2c/devices/i2c--1: No such file or directory
Unable to open directory /sys/bus/i2c/devices/i2c--1: No such file or directory
Unable to open directory /sys/bus/i2c/devices/i2c--1: No such file or directory
Unable to open directory /sys/bus/i2c/devices/i2c--1: No such file or directory
Device /dev/i2c-255 does not exist. Error = ENOENT(2): No such file or directory
/sys/bus/i2c buses without /dev/i2c-N devices: /sys/bus/i2c/devices/i2c-255
Driver i2c_dev must be loaded or builtin
See https://www.ddcutil.com/kernel_module
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =128
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =128
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =256
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =256
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =128
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =128
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =256
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =256
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =128
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =128
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =256
(i2c_ioctl_writer              ) Unexpected: ioctl() write returned 0
(i2c_ioctl_reader1             ) Unexpected ioctl rc = 0, bytect =256
Invalid display
   I2C bus:  /dev/i2c-9
   DRM connector:           card0-eDP-1
   EDID synopsis:
      Mfg id:               SHP - Sharp Corporation
      Model:                
      Product code:         5447  (0x1547)
      Serial number:        
      Binary serial number: 0 (0x00000000)
      Manufacture year:     2021,  Week: 52
   DDC communication failed
   This is an eDP laptop display. Laptop displays do not support DDC/CI.

Any idea how to handle this?