Version: 20180825+dfsg-1 I confirm the problem, it leads to a crash of the amdgpu module if the 4.19 kernel is booted with amdgpu.cik_support=1 radeon.cik_support=0
for further informations see https://bugs.freedesktop.org/show_bug.cgi?id=107855 comment 2 for the kernel messages and comment 4 for a simple workaround however the correct solution is to include the amdgpu firmware, as the radeon firmware seems to be no more updated ciao!
