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I am using Ubuntu 14.04 (Unity Desktop) on a Dell Inspiron 3531 laptop.

I tried connecting to an external monitor from my laptop's HDMI port. My laptop cannot connect. I ran xrandr. The xrandr says HDMI is disconnected. But strangely it says VGA is connected. This cannot be because my laptop has no VGA port. It only has HDMI.

I disconnected the HDMI cable from the HDMI port. Xrandr continue to indicate VGA is connected. So, I rebooted.

Even after rebooting, with no cable connection of any kind, then running xrandr, I continue to get a VGA is connected message.

What can I correct this?

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  • what is the output of xrand -q ? Edit your question and insert it
    – Maythux
    Apr 24, 2015 at 5:44
  • xrandr: Failed to get size of gamma for output default Screen 0: minimum 1366 x 768, current 1366 x 768, maximum 1366 x 768 default connected primary 1366x768+0+0 0mm x 0mm 1366x768 76.0*
    – Oscar M Sarmiento
    Apr 24, 2015 at 5:47
  • Please insert the output in the question in order to get help from others your question must be full understood with all your experminets to indicate the problem
    – Maythux
    Apr 24, 2015 at 5:48

2 Answers 2

Reset to default
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You have to add a new mode with a new resolution... You can do it and apply the new resolution using the command:

xrandr --addmode <connection_type> 1200x1000_60.00

Where <connection_type> is usually VGA1, DP1 or HDMI1.

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  • After adding new mode and issuing this command: xrandr --output HDMI1 --mode 1368x768_60.00 I got : xrandr: cannot find crtc for output HDMI1
    – Oscar M Sarmiento
    Apr 24, 2015 at 6:17
  • what is the output of this command?
    – Maythux
    Apr 24, 2015 at 6:18
  • After adding new mode and issuing this command: xrandr --output HDMI1 --mode 1368x768_60.00 I got : xrandr: cannot find crtc for output HDMI1
    – Oscar M Sarmiento
    Apr 24, 2015 at 6:20
  • This occurs becaues you have another screen already active,You can resolve this issue by simply turning off the screen using, xrandr --output VGA --off i suppose it's VGA based to your question
    – Maythux
    Apr 24, 2015 at 6:26
  • I issued 'xrandr --output VGA1 --off' and ran xrandr again and VGA1 remains connected.
    – Oscar M Sarmiento
    Apr 24, 2015 at 6:35
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I guess VGA1 is your laptop screen. To use the HDMI output you usually have to press a function key on the laptop keyboard. It should have an icon of a monitor on it. Connect the HDMI to a monitor then use the function key to toggle between VGA, HDMI and BOTH.

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  • I guess, you're right. I pressed f1 key and my laptop screen narrows in width. And pressing f1 again it goes back to full width screen. Perhaps, the problem is with my HDMI port. I bought this laptop on Sale and this may be one of the low-end models from Dell.
    – Oscar M Sarmiento
    Apr 24, 2015 at 7:51
  • Im using Mint at the moment, although i do use Ubuntu a lot on another PC. Have a look in the system settings, display section. Can you see that you have 2 monitors connected ? Are they both enabled ?
    – hatterman
    Apr 24, 2015 at 14:01

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