I found myself wrestling with XGA (1024×768) output on a system with only VGA output, although I was aware the display controller could get up to FHD easily (xrandr output shows the maximum “width” and “height” values surpassing that of FHD – see screenshot/s below).

I managed to wrangle the output to FHD by doing the following:

• get existing displays and note current display
  • xrandr --listmonitors
• get existing modes
  • xrandr
• if adding a new mode (e.g. forcing FHD aka 1080p aka 1920×1080 on a VGA output):
  • get new mode details
    • cvt <width> <height> <refresh rate>
    • e.g. cvt 1920 1080 60
  • copy the output after the “Modeline” – this will be the input for next command
  • create the new mode
    • xrandr --newmode <text after "Modeline" from cvt output>
  • add the new mode
    • xrandr --addmode <display> <mode name>
    • e.g. xrandr --addmode VGA-1 "1920x1080_60.00"
• change the mode
  • xrandr --output <display> --mode <mode name>

Making this stick was a completely different story in frustration…

Attempting to script this in a self-created /etc/profile.d/set-resolution.sh (and remembering to chown and chmod correctly), to ensure we can dynamically set the --newmode details (e.g. when moving the hard disk to another machine) was met with nothing but frustration…

Every method of “stripping” the “Modeline” text preface reply in-line did not work, from attempting to use awk to using parallel… xrandr‘s parsing of input is definitely non-standard.

I believe my only recourse would be to output text to script file on-the-fly, chmod the file and then execute the script… If I have the time, I will try just that and post an update here.