Possible Duplicate:
How well do laptops with Nvidia Optimus work?

My external monitor works fine when connected to my laptop's dock using a VGA cable. However, with a DVI cable, I can't seem to pick it up. Googling led me to install the NVIDIA additional drivers. After installation, I rebooted as instructed, and then tried to run NVIDIA X-server settings. I got a message telling me:

"You do not appear to be using the NVIDIA X driver. Please edit your X configuration file (just run `nvidia-xconfig' as root), and restart the X server."

However, after running `sudo nvidia-xconfig' and then "sudo service lightdm restart", my GUI fails to reappear. After removing the xorg.conf file created by nvidia-xconfig, I can get my laptop display back with "sudo service lightdm start", but I can't seem to actually get the NVIDIA drivers to work with X.

marked as duplicate by Lekensteyn, Takkat, Jorge Castro, fossfreedom, jrg Feb 16 '12 at 14:37

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  • What version of the NVidia driver did you install? – RobinJ Feb 13 '12 at 18:03
  • Looking on dell.com/us/enterprise/p/latitude-e6520/pd, it looks like an Optimus laptop. – Lekensteyn Feb 13 '12 at 18:33
  • @RobinJ: Not sure how to find out which version - there was one recommended option, and another "post-release-update" one - I tried both. – Steve Kroon Feb 14 '12 at 5:49
  • @Lekensteyn: My quote says "NVIDIA NVS 4200M 512MB Discrete Graphics", nothing about Optimus - also the Dell link you provide doesn't seem to mention Optimus either. – Steve Kroon Feb 14 '12 at 5:55
  • @SteveKroon Under the Video section, there are two cards: the intel one and "NVIDIA® NVSTM 4200M (DDR3 512MB) Discrete Graphics with Optimus" – Lekensteyn Feb 14 '12 at 9:04

I have the same laptop and problem here. I had it all working fine on 11.04. My upgrade to 11.10 gave me a lot of problems, I could not use my external monitor. So I enabled the Optimus setting in the bios and thus switched back to the Intel card only. My external monitor worked fine now using intel BUT no 3d rendering/compiz anymore which sucks.

I tried switching back to using the nvidia driver again today (by disabling optimus in the bios) and installing nvidia drivers. Unfortunately it did not work out and I switched back intel..Though I might have broken my installation a bit by my previous fixing attempts.. I do not want to spend much time on it again and continue working

I will try again when 12.04 comes out. They are working on improving the graphics stack.

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