tl;dr: startx xterm gives me the actual resolution of my display if I start it (from a vty) on kubuntu-desktop 18.04.05, but only 800×600 if I start it on ubuntu-server 18.04.04.
I am trying to set up a box with just the Xorg server running, as all clients will be connecting from inside docker containers. Think of it as a kind of kiosk. Here is what I am doing:
Disable sddm: systemctl stop sddm.service; systemctl disable sddm.service
Enable autologin on tty1 (per How can I get autologin at startup working on Ubuntu Server 16.04.1?)
Put exec startx xterm (well, my application actually) as the last time of the user’s .profile.
It works beautifully, but…
When I try the same on ubuntu-server rather than kubuntu-desktop (without the 1st line, of course), I only get an 800×600 display. I have installed all xserver-xorg-video-* packages. /var/log/Xorg.0.log looks pretty much the same in both cases. Before I start shaving more yaks, maybe someone has encountered this before and can give me a pointer?
This is on a NUC10i7FNK, with the built-in intel video.