Reducing resolution on HiDPI/4K displays for text-based installers

gistfile1.txt

I recently installed Ubuntu server on a laptop with a 4K display. While the installer appears to be in text, it apparently uses a graphical mode, and setting vga=799 in the kernl boot parameters did not work.

To decrease the resolution, you have to pass a kernel boot parameter with the monitor "name" as seen by edid.

You can do this to list monitors without xrandr

find /sys/devices -name "edid"

That will produce a listing like this:

/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-1/edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-VGA-1/edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/edid

a listing from xrandr would look like this:

Monitors: 3
 0: +*eDP-1 1920/381x1080/214+379+1440  eDP-1
 1: +VGA-1 1600/367x1200/275+2560+240  VGA-1
 2: +HDMI-1 2560/597x1440/336+0+0  HDMI-1

In my case, the laptop monitor is "eDP-1". I added the following to the grub kernel boot paramaters:

video=eDP-1:1920x1080@60

That made reading the screen much easier!