Comment # 20 on bug 1094834 from Takashi Iwai

Thanks for the information and testing.

Actually there is a known bug in Leap 15.0 GM kernel about nouveau, and that
might have hit you.

Could you try the kernel in
  http://download.opensuse.org/repositories/home:/tiwai:/bsc1094751/standard/
?

Try to boot this one without nouveau.modeset=0 option.