Theoretically, display server should be able to derive a proper DPI setting from EDID, but in reality this could fail at times. (eg. OS running in a VM.) In order to have things readable on HiDPI displays, we may have to adjust scaling factor manually.
GNOME
In terminal, run
gsettings set org.gnome.desktop.interface scaling-factor 2
To check your setting, dump dconf setting with
dconf dump /
or simply
dconf read /org/gnome/desktop/interface/scaling-factor
There should be something like
scaling-factor=uint32 2
GDM
For Debian-based distros:
- Edit
/etc/gdm3/greeter.dconf-defaultsas root - Add
[org/gnome/desktop/interface] scaling-factor=uint32 2
- Save and close the editor
- Finally, run as root:
dpkg-reconfigure gdm3
For other distros, check links below. π¬