Comment # 15 on bug 1200547 from Cliff Zhao

In this case, please press "Ctrl+Alt+F3", when you log in to the console, use
~> sudo plymouth quit
then press "Ctrl+Alt+F7", Check does the turning wheel never-ending disappear?
If it is, this is not plymouth's problem. 
After that, if you want us to do further works you have to switch the Display
manager to GDM, Because we(Desktop team) don't support SDDM. then please check
if your problem(as comment1 introduced) could reproduce, then feedback here.
But if you insist on using SDDM, you have to check the openSUSE community if
any people willing to support it.
Thank you.