Comment # 42 on bug 1180749 from Takashi Iwai

The amdgpu.backlight module option was already merged in the upstream, so TW
should have a workaround (passing amdgpu.backlight=0 boot option).  This was
also already merged in SLE15-SP3 / Leap 15.3 kernel, too.  But I don't think
we'd fix this for Leap 15.2.

The root cause of the problem hasn't been figured out yet.  My bet is that it's
a BIOS bug, and more proper workarounds are needed in AMDGPU driver side, but
this has to be sorted out in the upstream development.  Feel free to join to
the upstream gitlab Issues.