drm2, i915kms cause instant lock-up

[Konstantin Belousov]

On Tue, Feb 21, 2017 at 10:55:11AM -0800, Steve Kargl wrote:
> On Mon, Feb 20, 2017 at 09:26:58PM -0800, Steve Kargl wrote:
> > 
> > Well, the good news seems to be that r313254 and older are 'ok'.
> > So, something between r313943 and r313254 is triggering a the
> > problem.  I'm still bisecting, but it might take a day or two.
> > 
> 
> I've been able to narrow the range down to r313854 to r313943.
> If I had to guess, the issue may be related to 
> 
> Author: kib
> Date: Fri Feb 17 21:08:32 2017
> New Revision: 313898
> URL: https://svnweb.freebsd.org/changeset/base/313898
> 
> Log:
>   Merge i386 and amd64 mtrr drivers.
> 
> I won't be able to investigate until later tonight (~ 10 hours from now).

>From what I see in other messages, you are using i386 kernel on Core2
class machine, am I right ?  Did r313897 worked fine ?

r313898 has a bug for i386 architecture, which was fixed in r313934.
Could you compile kernel from r313898 sources with r313934 applied on
top of it ?  I mean, take r313898 and apply the changes from r313934
either manually or with patch, but not take any further changes from
svn after r313898.

If such kernel does not boot, I will provide further instructions.