This is my X log when trying to start on PI3.

X.Org X Server 1.17.2

Release Date: 2015-06-16

[   683.913] X Protocol Version 11, Revision 0

[   683.921] Build Operating System:  4.5.7-fedora-4 

[   683.930] Current Operating System: Linux centos-rpi3 4.4.33-v7.1.el7 #1 SMP Mon Nov 21 18:48:06 UTC 2016 armv7l

[   683.930] Kernel command line: 8250.nr_uarts=0 dma.dmachans=0x7f35 bcm2708_fb.fbwidth=1776 bcm2708_fb.fbheight=952 bcm2709.boardrev=0xa02082 bcm2709.serial=0x1fcfe9a2 smsc95xx.macaddr=B8:27:EB:CF:E9:A2 bcm2708_fb.fbswap=1 bcm2709.uart_clock=480

00000 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000  dwc_otg.lpm_enable=0 console=ttyS0,115200 console=tty1 root=/dev/mmcblk0p3 rootfstype=ext4 elevator=deadline rootwait selinux=1 security=selinux enforcing=0

[   683.969] Build Date: 09 November 2016  05:46:31PM

[   683.978] Build ID: xorg-x11-server 1.17.2-22.el7 

[   683.988] Current version of pixman: 0.34.0

[   684.007] Before reporting problems, check http://wiki.x.org

to make sure that you have the latest version.

[   684.007] Markers: (--) probed, (**) from config file, (==) default setting,

(++) from command line, (!!) notice, (II) informational,

(WW) warning, (EE) error, (NI) not implemented, (??) unknown.

[   684.045] (==) Log file: "/var/log/Xorg.0.log", Time: Mon Feb 13 13:36:06 2017

[   684.045] (II) Loader magic: 0x54cb3004

[   684.045] (II) Module ABI versions:

[   684.045] X.Org ANSI C Emulation: 0.4

[   684.045] X.Org Video Driver: 19.0

[   684.045] X.Org XInput driver : 21.0

[   684.045] X.Org Server Extension : 9.0

[   684.046] (II) no primary bus or device found

[   684.056] List of video drivers:

[   684.065] modesetting

[   684.065] (II) LoadModule: "modesetting"

[   684.066] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so

[   684.067] (II) Module modesetting: vendor="X.Org Foundation"

[   684.067] compiled for 1.17.2, module version = 1.17.2

[   684.067] Module class: X.Org Video Driver

[   684.067] ABI class: X.Org Video Driver, version 19.0

[   684.067] (WW) Falling back to old probe method for modesetting

[   684.076] No devices to configure.  Configuration failed.

[   684.077] (EE) Server terminated with error (2). Closing log file.