I am using a computer equipped with the GeForce GT 640 card, featuring one VGA port, two DVI ports and one HDMI port. For a long time, I have been using a single monitor plugged into the VGA port and it has worked fine.

I recently got a second monitor, which I plugged into the DVI port. For various reasons, I would like to keep my original monitor (on the VGA port) as the primary monitor. When I booted linux, the new monitor on the DVI port had, however, become the primary monitor. I tried to change this by going to Systems->Settings->Settings->Monitors, but was met with the message "could not get screen information". Note that this is translated to English, and might not be completely accurate.

How might I address this problem? Also, if would be happy to learn how to change screen/monitor settings from the command line.


*Debian: version 8.5

*Kernel: 3.16.0-4-amd64

*Gnome: GNOME Shell 3.14.4

  • 2
    What drivers are you using with the GeForce card? The proprietary ones, or the open source ones? The proprietary drivers, at least, have support for two monitors. Is that what you are using? Jun 17, 2017 at 10:28
  • I haven't manually installed any drivers, so I suppose I am using the open source ones. How can I check? Sorry if my questions are elementary, my debian skills are not so great. Jun 17, 2017 at 11:26
  • 2
    If you want someone to be notified, you need to put @username somewhere in the comment. If /etc/X11/xorg.conf exists and is non-empty, check what is under Driver. Section "Device" -> Driver "nvidia". You could also look at /var/log/Xorg.0.log to check what driver is being loaded. I normally recommend people using the proprietary Nvidia drivers, though I'm not a fan of proprietary software. But in the case of Nvidia cards, it generally is the better choice. Jun 17, 2017 at 12:31
  • @FaheemMitha Thanks! I couldn't find any xorg.conf file, nor could I locate the menu option you indicated. I looked at the log file /var/log/Xorg.0.log, and it appears that I am using a driver family called "Nouveau". Could this be correct? I managed to find the DVD for my GPU card, but naturally it only contains installation files for Windows. Jun 17, 2017 at 12:38
  • 1
    Yes, "Nouveau" is the free/open source software driver for Nvidia cards. You probably want to use the proprietary drivers. Fortunately it's quite easy to set this up for Debian. See wiki.debian.org/NvidiaGraphicsDrivers. That's also the top Google hit for "nvidia drivers debian". Ask if something seems unclear. Jun 17, 2017 at 12:45

1 Answer 1


The poster was using (or attempting to use) the free/open source Nouveau drivers. I suggested he use the proprietary Nvidia drivers, which I've found have generally superior functionality, plus have tools for configuration.

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