You have been subscribed to a public bug:
Ubuntu gnome 17.04, gnome 3.24. On high resolution display, 3200x1800,
login screen is too tiny to read. GDM login screen doesn't reflect
changes to org.gnome.desktop.interface scaling-factor or text-scaling-
factor.
Eg:
xhost +SI:localuser:gdm
sudo su gd
Public bug reported:
Ubuntu gnome 17.04, gnome 3.24. On high resolution display, 3200x1800,
login screen is too tiny to read. GDM login screen doesn't reflect
changes to org.gnome.desktop.interface scaling-factor or text-scaling-
factor.
Eg:
xhost +SI:localuser:gdm
sudo su gdm -s /bin/bash
gsetti