hi~ I just encountered the same problem as you on a pi3Pi 3 with the latest raspbian strectchRaspbian Stretch, luckily the seller of my touchscreen provided a solution and it works in my case. As he says this problem may because the xserver-xorg-input-evdevxserver-xorg-input-evdev
is not installed.
justJust execute:
sudo apt-get install xserver-xorg-input-evdev
sudo cp -rf /usr/share/X11/xorg.conf.d/10-evdev.conf
/usr/share/X11/xorg.conf.d/45-evdev.conf
afterAfter reboot my touchscreen worked correctly.