Comment # 14 on bug 1213438 from Takashi Iwai

Err, sorry, I was confused as if yours were with i915 graphics.  If it's
amdgpu, then this must be a different problem.

Still it might be worth to try, as it's built from the latest SLE15-SP5 kernel
git branch.

In general, a package from an OBS project can be downloaded from
  http://download.opensuse.org/repositories/...
For OBS home:tiwai:bscbsc1213493, it's
  http://download.opensuse.org/repositories/home:/tiwai:/bsc1213493/
(note the slash added around comma, i.e. ":" will be ":/")

Under subdirectory "pool/x86_64", you have kernel-default-$VERSION.rpm,
kernel-default-extra-$VERSION.rpm and kernel-default-optional-$VERSION.rpm.
Download those files, and install them via zypper install.  You might need to
pass --oldpackage option to zypper install, too.

And reboot, choose the kernel in GRUB menu, and boot with it / retest.