Comment # 5 on bug 1186896 from Takashi Iwai

The support of the recent AMDGPU stuff on Leap 15.2 kernel is fairly bad, and
it's unlikely that the fix will be taken for Leap 15.2 unless it's a trivial
fix.
So, let's concentrate on Leap 15.3.

Does Leap 15.3 kernel (with the update of kernel-firmware-amdgpu package) give
the same hang up at boot?  Or it's only about the brightness?

The brightness issue could be worked around by passing amdgpu.backlight=0
option (or 1) on the recent kernels.  For the Leap 15.3, you may try the kernel
in OBS Kernel:SLE15-SP3, too,
  http://download.opensuse.org/repositories/Kernel:/SLE15-SP3/standard/