I just tried a minimal installation of Debian. After completion, I installed Nvidia driver, Xorg and KDE Plasma.
Now it is time to startx. However, xserver refuses to start, claiming "no screens found".
After several attempts I found out that GUI will start IF AND ONLY IF /etc/X11/xorg.conf DOES NOT EXIST. The config file was generated using nvidia tool. And the only suspicious section is the Monitor section saying ModelName and VendorName are unknown.
I think the problem will be solved if I can generate monitor info and fill that into xorg.conf. But I don't know how. Please help. Or state your thoughts of what's going wrong.