FWIW I’ve been experimenting with gamescope a lot yesterday, it’s been a mess:
- from a TTY, I can use gamescope to run steam in a session, but it doesn’t have sound
- steam -gamepadui (to have the same UI as the steam deck) can be run but games windows aren’t shown
(not even specific to gamescope) - steam flatpak + gamescope flatpak allows to start games with a gamescope command line, and it’s working fine
- nixos steam + nixos gamescope can’t be used per game because of the /tmp/.X11-unix issue
- running steam with gamescope entirely is working fine, if so I recommend the following command:
gamescope -f -e -U -- steam -tenfoot, it displays steam in big picture mode (otherwise it displays a loading screen and nothing else ), and this doesn’t enforce a resolution for the games/steam, but if you reduce resolution in-game, then FSR kicks in, I find it a lot more practical this way as it’s wrapping steam and all games… - I couldn’t get mangohud to work with flatpak (using it from flatpak)
- with gamescope, you need mangoapp and not mangohud, and it is started differently, like in this example
gamescope -- /bin/sh -c 'mangoapp& steam'