Comment # 1 on bug 1013555 from Takashi Iwai

Try to install openSUSE 42.1 kernel onto openSUSE 42.2 system.
zypper may give some errors, and it'd be maybe easier to install directly via
rpm like:
  rpm -ivh --nodeps --force kernel-default-*.rpm

And check with radeon driver, without fglrx.

If this works, it's a kernel regression.  If the problem happens with 42.1
kernel, it's a regression in user-space X side.