I have some new information. Apparently, I tried a different external monitor with the displayport and the same 2560x1600 resolution and the laptop worked just fine. I can run xrandr or unity-control-center while the monitor is connected and there are no issues.
The monitor that does not work correctly has a display port->dvi adapter and the resolution is not detected correctly. Because of that, I manually add the resolution each time the computer boots with the following command: xrandr --newmode 2560x1600 268.00 2560 2608 2640 2720 1600 1603 1609 1646 -hsync +vsync; xrandr --addmode DP1 2560x1600; xrandr --newmode 1280x800 71.00 1280 1328 1360 1440 800 803 809 823 -hsync +vsync; xrandr --addmode DP1 1280x800 And then I set the output to the monitor with the following command: xrandr --output LVDS1 --off --output VGA1 --off --output HDMI1 --off --output DP1 --mode 2560x1600 Therefore it is likely that this is a bug related to the display port->dvi adapter. -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1314213 Title: [Lenovo ThinkPad X220] External DP1 monitor extremely unstable since upgrade to 14.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1314213/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : [email protected] Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
