When I boot Ubuntu, the system has the correct screen resolution until the login screen is displayed. It then temporarily changes to a much lower resolution and restores the original resolution after login.

As far as I understood, the login screen is realized with GDM (used to be LightDM). The posts I read so far recommend to put fix this directly in /etc/gdm3/Init/Default by adding the appropriate xrandr command right before exit 0, in my case xrandr --output XWAYLAND0 --primary --mode 2560x1440.

After reboot the login screen is still displayed in the wrong resolution or the zoom factor is doubled, which I cannot check.

As the recommended fix does not work: How can I check why it is not working and how can I fix this issue?

  • I have a similar laptop, Lenovo X1-Yoga and I have the same issue you have. Have you found anything since your post about a year ago? – Alex Oct 24 '18 at 23:45
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    @Alex unfortunately not. I assume that the login screen resolution might be correct, but maybe the login screen itself is maybe enlarged by some factors. It is a shame that there is no easy tweaking for that specific issue. Once I would have found a workaround, I would post it here immediately. – Vince42 Oct 25 '18 at 15:55

The mode you are trying to set may not be available to xrandr yet. In your /etc/gdm3/Init/Default, put the following also before the exit 0.

xrandr --newmode "2560x1440_60.00"  312.25  2560 2752 3024 3488  1440 1443 1448 1493 -hsync +vsync
xrandr --addmode XWAYLAND0 "2560x1440_60.00"
xrandr --output XWAYLAND0 --primary --mode "2560x1440_60.00"
exit 0
  • Thank you for your suggestion, but unfortunately it did not work. Apart from the hardware I am still also suspecting some "zoom setting" or another tweaking option - but only time will tell. It is not, that I am unable to login - but it looks so terribly ugly with the big font and graphics. ;) – Vince42 Dec 4 '17 at 23:14

The display rendering most likely depends on your exact video card.

When the system boots is "auto" checks for very detailed features in some video cards and "not others?" Your video card is maybe much more then just the screen size? Some of these features are "generic" and usually can be read from memory address locations on the card AND others custom or problem video locations.

From what I hear there is kinda a debate between the passing of the old display driver system and the new so stability of how detailed info can truly be read from the video card is not always possible and people maybe needs to be "translated". You can maybe contact the owner of the video driver for your card? Of post some more detailed info.


  • They must have changed it two years ago - before that my graphics card has always been detected properly. Mine is a built-in Intel in a Lenovo X1 Carbon 4th Generation - which should not be very exotic. Which detailed info would help? – Vince42 Dec 4 '17 at 23:12

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