Only works for one (out of three) display port
After installation, I can change brightness for external display, but only if it's plugged into a specific port. I don't really know what I am doing (this is the first time I loaded a kernel module!), but I noticed that the port that works, contains ddcci_backlight
folder, whereas other don't:
❯ ls /sys/devices/pci0000:00/0000:00:08.1/0000:33:00.0/drm/card1/card*
'/sys/devices/pci0000:00/0000:00:08.1/0000:33:00.0/drm/card1/card1-DP-1':
ddc ddcci_backlight device dpms drm_dp_aux1 edid enabled i2c-12 modes power status subsystem uevent
'/sys/devices/pci0000:00/0000:00:08.1/0000:33:00.0/drm/card1/card1-DP-2':
ddc device dpms drm_dp_aux2 edid enabled i2c-13 modes power status subsystem uevent
... // other entries including laptop display
'/sys/devices/pci0000:00/0000:00:08.1/0000:33:00.0/drm/card1/card1-HDMI-A-1':
ddc device dpms edid enabled modes power status subsystem uevent
Is there a way to control brightness regardless of the port?
Thank you for your help and great work!