freebsd stable - Oct 2017 - Support of the Intel HD 4600 (Haswell) graphics seems to be broken

Hi,

I've FreeBSD 11.1-RELEASE-p1 installed on an Intel Core i7 4790 based
machine. I use the CPU integrated HD 4600 graphics and its support
seems to be broken.

Can't start Lumina and Xfce. Can start the standard xorg's twm
(startx) but Firefox can't use DRM or D-Bus and crashes. See
screenshots of errors saved at the following URLs:

http://i66.tinypic.com/287k5s2.jpg
http://i66.tinypic.com/33bmko4.jpg

Xorg logs have no error.

Is it a known issue? Any workaround?