Built-in display detected as external one

That's the problem, for some reason my laptop's display is detected as an external display so that's preventing backlight control from working. Any idea on how to solve this? My laptop's model is Asus GL552VW with intel hd 530 graphics.

https://preview.redd.it/ktxa5pz3wxg71.png?width=1920&format=png&auto=webp&s=b061a92d971123a13536f88f83b74749a6b9cdd2