X server doesn't work on Ubuntu 14.04. What may be happening?

Question

This how I used to setup my X Server on Ubuntu 13.

apt-get update
apt-get upgrade

# nvidia
apt-get -y install nvidia-current
apt-get -y install nvidia-current-updates

# x server
apt-get -y install xserver-xorg
apt-get -y install x11-xserver-utils

export DISPLAY=localhost:0.0

X :0 &
xhost +

On Ubuntu 14, I am getting the following error when I do X :0:

[  3491.124] (II) Module wfb: vendor="X.Org Foundation"
[  3491.124]    compiled for 1.15.1, module version = 1.0.0
[  3491.124]    ABI class: X.Org ANSI C Emulation, version 0.4
[  3491.124] (II) Loading sub module "ramdac"
[  3491.124] (II) LoadModule: "ramdac"
[  3491.124] (II) Module "ramdac" already built-in
[  3491.125] (**) NVIDIA(0): Depth 24, (--) framebuffer bpp 32
[  3491.125] (==) NVIDIA(0): RGB weight 888
[  3491.125] (==) NVIDIA(0): Default visual is TrueColor
[  3491.125] (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0)
[  3491.125] (**) NVIDIA(0): Enabling 2D acceleration
[  3491.569] (II) NVIDIA(0): NVIDIA GPU GeForce GTX 650 Ti (GK106) at PCI:1:0:0 (GPU-0)
[  3491.569] (--) NVIDIA(0): Memory: 2097152 kBytes
[  3491.569] (--) NVIDIA(0): VideoBIOS: 80.06.3c.00.11
[  3491.569] (II) NVIDIA(0): Detected PCI Express Link width: 16X
[  3491.569] (--) NVIDIA(0): Interlaced video modes are supported on this GPU
[  3491.572] (--) NVIDIA(0): Valid display device(s) on GeForce GTX 650 Ti at PCI:1:0:0
[  3491.572] (--) NVIDIA(0):     CRT-0
[  3491.572] (--) NVIDIA(0):     DFP-0
[  3491.572] (--) NVIDIA(0):     DFP-1
[  3491.572] (--) NVIDIA(0): CRT-0: 480.0 MHz maximum pixel clock
[  3491.572] (--) NVIDIA(0): DFP-0: 165.0 MHz maximum pixel clock
[  3491.573] (--) NVIDIA(0): DFP-0: Internal Single Link TMDS
[  3491.573] (--) NVIDIA(0): DFP-1: 330.0 MHz maximum pixel clock
[  3491.573] (--) NVIDIA(0): DFP-1: Internal Single Link TMDS
[  3491.573] (EE) NVIDIA(0): Failed to assign any connected display devices to X screen 0
[  3491.598] (EE) NVIDIA(0): Failing initialization of X screen 0
[  3491.782] (II) UnloadModule: "nvidia"
[  3491.782] (II) UnloadSubModule: "wfb"
[  3491.782] (II) UnloadSubModule: "fb"
[  3491.782] (EE) Screen(s) found, but none have a usable configuration.
[  3491.782] (EE) 
Fatal server error:
[  3491.782] (EE) no screens found(EE) 

What else can be done?

Answer 1

I found the final solution here: http://www.nvidia.com.br/download/driverResults.aspx/69539

There's an item it says:

• Add a new option, AllowEmptyInitialConfiguration, which allows the X server to start even if no connected display devices are detected at startup. This option can be enabled by running "sudo nvidia-xconfig --allow-empty-initial-configuration"

So I did:

sudo nvidia-xconfig --allow-empty-initial-configuration

And it worked.

It happened because this is a server and in fact it doesn't have any display device connected.

Also, before it I followed the advice of bodhi.zazen. I blocked the nouveau drivers [and other stuff I think]

I added to /etc/modprobe.d/blacklist.conf

blacklist vga16fb
blacklist nouveau
blacklist rivafb
blacklist nvidiafb
blacklist rivatv

Then I rebooted, reinstalled the NVDIA drivers... and rebooted again!

Answer 2

I had the exact same problem. ensuring the dvi cable was correctly fixed was the solution.

Actually the nvidia driver seem to be checking the connection with the screen, so even so when the screen seems to display correctly and nouveau driver works, an incorrect connection can prevent the nvidia driver to work.