Xorg in Ubuntu how to add drm device?

Question

X.Org

There is an updated to 14.04.5 Ubuntu. It has a working configuration on the 3.19.0-80 kernel and a partially working configuration on the 4.4.0-74 kernel. Partially works because of the nomodeset parameter, without it a dull black screen.
In the logs, I finally found a difference in the latest kernel, xorg.0.log is missing the line "xfree86: Adding drm device (/dev/dri/card0)".
Well, it's clear that after that:
[ 27.273] (EE) open /dev/dri/card0: No such file or directory
[ 27.273] (WW) Falling back to old probe method for modesetting
[ 27.273] (EE) open /dev/ dri/card0: No such file or directory
How would you put everything back in place?