Backlight is stuck

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Hi, I recieved my new Lenovo Thinkpad X1 Yoga (OLED Display) today and noticed that under Fedora 26 my screen backlight is stuck at 100%. Neither via the gnome control center nor xrandr it is possible to change that. Xbacklight returns only "No outputs have backlight property" and trying

sudo ln -s /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/brightness /sys/class/backlight/

returned only

ln: die symbolische Verknüpfung '/sys/class/backlight/brightness' konnte nicht angelegt werden: Operation not permitted

. I've also tried adding "acpibacklight=vendor" to /etc/default/grub at the end of GRUBCMDLINE_LINUX and creating the xorg.conf file containing

Section "Device"
Identifier  "Card0"
Driver  "intel"
Option  "Backlight"  "intel_backlight"

EndSection

I hope you can help me.

Yours, deltavii