Comment 2 for bug 1446760

I copied your report and edited in my on-upstart observations:

I got the prompt asking me whether I wish to run lightdm or sddm and I chose lightdm. However after reboot I got a text login on TTY1. (NOTE: Very fast, a fraction of time needed for reaching a login manager on that machine)

Running "service lightdm status && service sddm status" told me that they both were STOPPED.
I could run "service lightdm start" or "service sddm start" to start either one manually, but not automatically.

So it's not just on systemd.

NOTE: Even though I selected "lightdm" during sddm installation,
/etc/X11/default-display-manager was still overwritten to says "/usr/bin/sddm"
I fixed that by working around #1422247 and deinstalling sddm.