I have an old Dell Vosto 1700 running Debian Linux Trixie. It has a G86M (GeForce 8400M) graphics chip. I’ve installed the 340 driver. If I connect an additional monitor to the VGA port, nvidia-settings detects it but turns it off. If I turn it on and move it to the right of the main screen to correspond to the physical layout, and push the “apply” button, it eventually fails with a complaint about not being able to set a mode.
If I set up the system manually using xorg.conf and start with startx, the dual-monitor system works, but I’d rather log in with SDDM and use the nvidia-settings widget.
Is there a file somewhere that I can edit?