Xorg: ../../include/privates.h:122: dixGetPrivateAddr: Assertion `key->initialized' failed.

X.Org X Server 1.18.4
Release Date: 2016-07-19
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.4.0-83-generic x86_64 Ubuntu
Current Operating System: Linux OptiPlex-GX620 4.4.0-93-generic #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC 2017 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-93-generic root=UUID=9b3768b1-7ec8-4d00-8047-4e66b6d7c008 ro quiet splash vt.handoff=7
Build Date: 17 July 2017  05:05:12PM
xorg-server 2:1.18.4-0ubuntu0.3 (For technical support please see http://www.ubuntu.com/support) 
Current version of pixman: 0.33.6
	Before reporting problems, check http://wiki.x.org
	to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Aug 28 14:52:35 2017
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(II) [KMS] Kernel modesetting enabled.