[opensuse] No keyboard backlight since 4.18.x kernels

Hi all, My problem is in the subject. I even cannot find anymore where ccould I set it. I have two ASUS laptops, from the K501U series, but they are non identical. Keyboard backlight is lost on both of them. The last 4.17.x kernel had/has keyboard light. I waited for updates but with the coming of 4.18.6 kernel the lights are still lost. Albert