The xf86-video-nouveau driver as of today supports server-managed file descriptors. As explained in the earlier Phoronix article, Last month we wrote about Red Hat working on a suid root wrapper for the X.org Server and other improvements being led by Red Hat's Hans de Goede to run Xorg in more configurations without needing root support. As part of this, sever managed file descriptors (FDs) has been one of the changes needed by the X.Org graphics drivers for supporting this change of running the xorg-server without root rights. Besides needing changes to the DDX drivers and the X.Org Server (those changes are landing with X.Org Server 1.16 this summer), systemd-logind is also needed.
It was with this Git commit that the Nouveau DDX got the server managed FD treatment. Today's xf86-video-nouveau driver activity for this change were the first Nouveau DDX commits to mainline since November of last year with most work going into the Nouveau Gallium3D drivers and the DRM/KMS kernel driver.
Besides the X.Org Server supporting more configurations without needing root privileges, the X.Org Server 1.16 release due out in July also has the merging of GLAMOR and its tons of changes and initial XWayland support.