Maxium Resolution resets to 1024x768 after logout [duplicate]

Question

The Display Settings maximum resolution started at 1024x768(4:3)

I tried to use xrandr like so:

>>xrandr
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
DVI-I-1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0* 
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9  
DVI-I-2 disconnected (normal left inverted right x axis y axis)

>>cvt 1900:900
# 1600x900 59.95 Hz (CVT 1.44M9) hsync: 55.99 kHz; pclk: 118.25 MHz
Modeline "1600x900_60.00"  118.25  1600 1696 1856 2112  900 903 908 934 -hsync +vsync

>>xrandr --newmode "1600x900_60.00"  118.25  1600 1696 1856 2112  900 903 908 934 -hsync +vsync

>>xrandr --addmode DVI-I-1 1600x900_60.0

>>xrandr
Screen 0: minimum 320 x 200, current 1600 x 900, maximum 8192 x 8192
DVI-I-1 connected primary 1600x900+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0  
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9  
   1600x900_60.00   59.9* 
DVI-I-2 disconnected (normal left inverted right x axis y axis)

At this point my display changes to 1600x900.

But after I log-out or reboot it goes back to 1024x768 and I have to re-do this process.

Essentially this is the same as this other question which only mentions

There is also a section about Setting xrandr changes persistently which can help if the resolution you set does not stay after you reboot.

But I couldn't find it.

Here's the error message I get after reboot:

Answer 1

Type your xrandr --newmode and xrandr --addmode commands into a text file. In my case I also needed a xrandr --output command which I also put in this text file. Make this file executable.

Then edit (using sudo) /etc/lightdm/lightdm.conf and in the [SeatDefaults] section add

display-setup-script=[path to the text file you made]

This will set up and select your new resolution before the login screen appears. Alternately, to set the screen up at login instead (I have not done this myself) you can add

session-setup-script=[path to the text file you made]