drm2, i915kms cause instant lock-up

[Steve Kargl]

On Tue, Feb 21, 2017 at 12:58:07AM +0100, Mateusz Guzik wrote:
> On Mon, Feb 20, 2017 at 03:52:24PM -0800, Steve Kargl wrote:
> > With a kernel and world from r313943 sources (circa
> > Feb 19, 2017), kldload of either drm2.ko or i915kms.ko
> > will lock up the system.  There is no keyboard response,
> > screen output, or panic.  Just a locked up system.
> > 
> > A kernel from r313027 and its modules boots fine.
> > 'kldload drm2.ko' yields the following in /var/log/messages:
> > 
> 
> There were quite a few invasive changes in this timeframe. Can you
> please:
> 
> 1. switch to 313254 and ensure it works
> 2. apply https://people.freebsd.org/~mjg/patches/complete-locks.diff and
> check if it breaks
> 
> If it does not break, revert the patch and bisect the kernel please.
> Otherwise I'll devise smaller diffs to narrow this down.
> 

With 1. and 2. the system boots and I can kldload both drm2
and i915kms.  I revert the patch and start bisecting the kernel.
Thanks for the quick response.

-- 
Steve
20161221 https://www.youtube.com/watch?v=IbCHE-hONow