I have a 60Hz computer monitor and a projector with 24Hz support (Optoma UHD40) — I run the devices at different refresh rates (60 and 24Hz, or specifically 23.98Hz) and I’m only given an option to ‘join’ or ‘mirror’ the displays:
‘join’ has to be selected in order to getting access to refresh rate options
askubuntu.com implies that the single-display option has been around at least since Gnome 40.4.0:
I don’t have any need to output to several displays at once since I only ever focus on and view one at a time. This configuration may be a major potential source of errors — after some testing it appears that mpv drops frames with 23.976fps content (24p) if both devices aren’t set to run at 60Hz. The
--video-sync=display-resample option also appears to suffer from major performance issues, and was mostly fine after disconnecting the monitor.
In short, please show how to set up (“force” if required) a single-display mode in Gnome and speculate why the mode may not be available to me.
Fedora 36, Gnome…
$ cat /usr/share/gnome/gnome-version.xml:
<gnome-version> <platform>42</platform> <minor>2</minor> <micro>0</micro> <distributor>GNOME.Org</distributor> <date>2022-06-03</date> </gnome-version>