https://bugs.freedesktop.org/show_bug.cgi?id=107333
--- Comment #2 from Benjamin Hodgetts ben@xnode.org --- By "forced" I mean I specified amdgpu.dc=0 on the kernel command line to force DC off (as it's on by default).
Yes to the second part of your question. Using dc=0 allows the display to be properly detected, even if it's turned off.