I'm afraid I have to reassign this back to the kernel. In comment 4 it is shown that the Fn+Fx keys work, but the topmost keys (labelled "3" in your image) all generate the same scan code 0x8D, so it's impossible to assign these to a keycode. These scan codes need to be fixed in the driver, or it could even be possible that the non-Windows ACPI tables of these Samsung models are just broken.
The other issue is that the keyboard backlight key produces the correct keycode, but userspace does not actually handle it. That is tracked in bug 1203592.
I'm afraid I have to reassign this back to the kernel. In comment 4 it is shown that the Fn+Fx keys work, but the topmost keys (labelled "3" in your image) all generate the same scan code 0x8D, so it's impossible to assign these to a keycode. These scan codes need to be fixed in the driver, or it could even be possible that the non-Windows ACPI tables of these Samsung models are just broken.
The other issue is that the keyboard backlight key produces the correct keycode, but userspace does not actually handle it. That is tracked in bug 1203592.