Comment # 13 on bug 108577 from Duncan Roe

Rebuilt b646c1dc835b6b73884a88643c2534f1a4a1928f (previously OK) with
CONFIG_DRM_AMD_DC_FBC turned on and got a black X display.
The Help for this option says to check hardware availability before enabling.
Looks like my hardware doesn't have it.
I can see no way this option should be forced on. What I think was intended was
to remove CONFIG_DRM_AMD_DC as an option instead.