The fbdev potential for deadlock may be years old, but the warning
(and consequent disabling of lockdep from that point on - making it
useless to everybody else in need of it) is new, and comes from the
commit below in linux-next.

I revert it in my own testing: if there is no quick fix to the
fbdev issue on the way, Daniel, please revert it from your tree.

If you revert it you swap it for a different deadlock - and one that
happens more often I would expect. Not very useful.

I'm hoping the framebuffer maintainer will bother to respond to this
because that's the only way it can be sorted out.

Alan