https://bugzilla.kernel.org/show_bug.cgi?id=71461
--- Comment #27 from Tom Yan tom.ty89@gmail.com --- (In reply to Alex Deucher from comment #25)
(In reply to Tom Yan from comment #23)
Btw, is it something not implemented yet or a bug, that it won't do the modesetting later if no device plugged before boot? Why does it have to go 1024x768? I mean, why does it require a device to initialize "dynamic" modesetting?
It's a bug that seems to be specific to your board. The vast majority of cards work fine (i.e., you can dynamically change monitors on the fly).
I can dynamically change monitors, just that the prequisite is something has to be connected (and turned on unless it's DVI) before boot.
I have two different cards sharing the same problem, though they are both from Sapphire. I'll see if I can test one from others.