https://www.illumos.org/issues/12473
5 seconds delay may be too short for Xorg to exit

--- lightdm-1.28.0/src/process.c-orig	Sat Apr 11 19:09:08 2020
+++ lightdm-1.28.0/src/process.c	Mon Apr 13 14:53:16 2020
@@ -342,8 +342,8 @@
     if (priv->pid == 0)
         return;
 
-    /* Send SIGTERM, and then SIGKILL if no response */
-    priv->quit_timeout = g_timeout_add (5000, (GSourceFunc) quit_timeout_cb, process);
+    /* Send SIGTERM, and then SIGKILL 60 seconds later if no response */
+    priv->quit_timeout = g_timeout_add (60000, (GSourceFunc) quit_timeout_cb, process);
     process_signal (process, SIGTERM);
 }