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When I run xrandr on the terminal I see DVI-0 connected and DisplayPort-1 connected. I only use DVI-0 as my output. I don't have two screens, or anything else connected to my computer, so I don't know why DisplayPort-1 is even presented. I use an HDMI to DVI adapter..

Since DisplayPort-1 is presented, I am getting some weird behavior when changing the resolution. If I run xrandr -s 1024x768 and I was previously in a resolution of 800x600, then I will get a cut off screen because for some reason I'm changing the resolution of the DisplayPort. This also happens going the other way, from 1024x768 to 800x600.

In the past I would add video=DP-1:d to the grub boot options to hide this "phantom" display. This would fix all the funny problems. However, this grub option no longer works! After adding it to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub and doing an update-grub, the computer still comes up with the phantom DisplayPort-1 output.

I'm running Ubuntu 14.04.2 LTS. Any ideas?

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  • Can you clarify what is fixed and your video card ?
    – Panther
    Jan 8, 2016 at 19:31
  • When I add "video=DP-1:d", then I can change the resolution from 800x600 to 1024x768 without any screen-cut offs. The only output device I see when I do xrandr is then DVI-0 which is what I would expect, because that's the only device that is plugged in. I don't even have a DisplayPort!
    – Gabe
    Jan 8, 2016 at 19:56
  • Here is a link to the output ( pastebin.com/AdDnfBuF ) of lshw and my video card: *-display description: VGA compatible controller product: Atom Processor D2xxx/N2xxx Integrated Graphics Controller
    – Gabe
    Jan 8, 2016 at 19:58
  • Looks like a gma500 . What graphics problem are you having ? should have native resolution (1366x786)
    – Panther
    Jan 8, 2016 at 20:47
  • 2
    @Gabe You should post an answer below :)
    – Seth
    Jan 14, 2016 at 0:16

1 Answer 1

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I was able to disable the display port by adding video=DP-2:d to the grub boot options. Notice that xrandr was showing DisplayPort-1 even though in reality DP-2 was enabled.

Here's how I was able to find out which was the real output device thanks to the ArchLinux wiki:

*To get the name and current status of connectors, you can use the following shell one-liner:

$ for p in /sys/class/drm/*/status; do con=${p%/status}; echo -n "${con#*/card?-}: "; cat $p; done

DVI-I-1: connected
HDMI-A-1: disconnected
VGA-1: disconnected
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  • Can you post your XRANDR output. I want to understand why we need to add DP-2:d
    – Ragav
    Feb 3, 2016 at 12:31

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