drivers - NVIDIA: GPU exception occured durint X server init

My GPU is the GTX870M. I did a fresh install of Ubuntu 18.04. All I did was:

sudo apt-get update
sudo apt-get upgrade
sudo ubuntu-drivers autoinstall
nvidia-xconfig
reboot

It installed the nvidia-390 driver. Now whenever I try to start the X server with startx it fails. I can still use Wayland. Here is what I tried (in recovery mode):

startx

Output:

X.Org X Server 1.20.1
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.4.0-140-generic x86_64 Ubuntu
Current Operating System: Linux -PC 4.18.0-22-generic #23~18.04.1-Ubuntu SMP Thu Jun 6 08:37:25 UTC 2019 x86_64

Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.18.0-22-generic root=UUID=0d1d9304-4cd6-41f6-80b2-3562578a252e ro recovery nomodeset
Build Date: 27 November 2018  05:27:12PM
xorg-server-hwe-18.04 2:1.20.1-3ubuntu2.1~18.04.1 (For technical support please see http://www.ubuntu.com/support) 
Current version of pixman: 0.34.0
    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: Sat Jun 22 13:47:29 2019

(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(EE) 
Fatal server error:
(EE) NVIDIA: A GPU exception occurred during X server initialization(EE) 
(EE) 
Please consult the The X.Org Foundation support 
     at http://wiki.x.org
 for help. 
(EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.

(EE) 
(EE) Server terminated with error (1). Closing log file.
xinit: giving up
xinit: unable to connect to X server: Connection refused
xinit: server error

/var/log/Xorg.0.log: https://pastebin.com/ygxRKPpg

In these logs, 2 things caught my eyes:

[   119.994] (II) NVIDIA(0): Virtual screen size determined to be 640 x 480
[   119.994] (WW) NVIDIA(0): Unable to get display device for DPI computation.

and

[   119.994] (--) NVIDIA(0): Memory: 3145728 kBytes
[   119.994] (II) NVIDIA: Using 6144.00 MB of virtual memory for indirect memory

It seems like my display device is not correctly detected and/or that X server is trying to use too much memory?

dmesg output: https://pastebin.com/fcYMPrUB

Relevant parts:

[  120.275346] NVRM: GPU at PCI:0000:01:00: GPU-c588f20e-6b26-3352-5b81-666db3c970a2
[  120.275348] NVRM: Xid (PCI:0000:01:00): 44, Ch 00000000, engmask 00000101, intr 10000000
[  120.793329] NVRM: Xid (PCI:0000:01:00): 31, Ch 00000008, engmask 00000111, intr 10000000

I checked what the Xid meant: https://docs.nvidia.com/deploy/xid-errors/index.html

31 GPU memory page fault

44 Graphics Engine fault during context switch

nvidia-smi output:

Sat Jun 22 14:23:52 2019       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 390.116                Driver Version: 390.116                   |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 870M    Off  | 00000000:01:00.0 N/A |                  N/A |
| N/A   83C    P0    N/A /  N/A |      0MiB /  3018MiB |     N/A      Default |
+-------------------------------+----------------------+----------------------+


+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0                    Not Supported                                       |
+-----------------------------------------------------------------------------+

Any help is appreciated, thanks.