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I have just installed Ubuntu 12.04.1 LTS in my computer with 2 monitors, but when I open "Displays", just one is shown.

Im running a NVIDIA card.

If you need anymore information, tell me and Ill add it.

What am I missing?

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up vote 0 down vote accepted

You will need to install the NVidia drivers, if you have not already. You should be able to find these under System Settings -> Additional Drivers -> NVIDIA accelerated graphics driver (version current).

Unfortunately, the NVidia binary drivers do not fully stick to standards for describing multiple monitors. The System Settings -> Display window will show only a single large "screen" spanning both monitors. To configure your dual monitors, you need to use the NVidia X Server Settings tool which should have been installed along with the drivers.

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Simple as that! thanks! – Dbugger Oct 10 '12 at 10:18
maybe its going offtopic, but how can I remove the "sticky edges" if I cant use the "Display" window? – Dbugger Oct 10 '12 at 11:02

Essentially this fix should solve the Dual screen not recognized problem. It did for me.

Symptoms I was encountering were:

sudo /usr/lib/nux/unity_support_test -p
Error: no composite extension.

Additionally when I attempted to open the Displays setting dialog, it would error saying something about RANDR and then never open even crashing Ubuntu a few times presenting the reporting dialog.

Some back story: I have an nVidia GeForce 8800GTS. When I booted the LiveCD of 12.04LTS 32bit, it booted with a fancy high-resolution grub, high resolution text mode, and right into unity with full 3D. After a while, ubuntu told me about proprietary drivers I should install, so I did. I installed the [recommended] one but upon rebooting, unity was stuck in 2D mode. So began my search for the fix.

I had been fighting with this issue for the past few days and successfully got unity running in 3D again by doing the following steps:

What I did to fix it:

  1. Get the latest nVidia drivers:
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get dist-upgrade
  1. Modify grub to pass in nomodeset (this in combination with #3 did it I think)
sudo nano /etc/default/grub (and uncomment the GRUB_GFXMODE)

sudo nano /boot/grub/grub.cfg
linux /boot/vmlinuz-3.2.0-32-generic-pae root=UUID=a9aa4a63-ac9c-4fc4-96d8-7861d155d376 ro   quiet splash $vt_handoff nomodeset   
sudo update-grub
  1. Force nvidia-xconfig to run for composite.
sudo service stop lightdm     
sudo nvidia-xconfig --composite   
sudo service start lightdm

So, in all I think it was step 1, and 3 that fixed this for me. Step 2 just made the boot graphics high-res and gave me the super fine text mode I had on my install.


To solve the dual displays issue, I was encountering and giving me access to the Displays settings, I had to stop using xinerama and switch to using Twinview in the nvidia-settings program.

I erroneously thought this would clone/mirror the displays and was using xinerama instead thinking that was the only way I could get both displays to work, but TwinView does exactly what I want; and because I'm no longer using xinerama, Ubuntu Display settings dialog does open (before it was showing RANDR error) and shows two displays.

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Is this answer intended to address the question above? You might be better off asking and answering a new question yourself if you'd like to share this information. – Mark Paskal Oct 15 '12 at 7:00
Yes, my answer is intended to address the question above. It answers a little bit more than just that question, which I hope someone may find useful. I've made edits to clarify these things. Thank you for giving me the advice though as it reminded me I left out the TwinView step in what I did to get this to work. – grymmjack Oct 15 '12 at 11:09

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