drm-fbsd11.2-kmod on 12

[Matthew D. Fuller]

On Fri, Nov 08, 2019 at 09:46:43AM +0100 I heard the voice of
Niclas Zeising, and lo! it spake thus:
> 
> I don't know if it is simple or not.  The code is there, if you can
> get it running on 12.1 without breaking 11.3, then, by all means do
> it.

FWIW, just cherrypicking back 9e308e6a707bc29 (adding pcpu.h to one
file) from the 4.16-12.0 branch sufficed to get it building and
basically running.  I also pulled back 324a27a734733 (DRM_SYSCTL_PRINT
locking) and 148d05832cc12 (enable MSI) since they seemed like good
things.  Apart from a little trivial conflict resolution on the
latter, it all Just Happened.

In a solid 5 minutes of running it and testing a little video playing
(on the system where 4.16 is stable aside from the videos), it hasn't
blown up yet.  I'll see if something happens over the next few days.


-- 
Matthew Fuller     (MF4839)   |  fullermd at over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
           On the Internet, nobody can hear you scream.