It's a common scenario that folks left ChimeraOS (Steam OS-ish Linux bistro) idle while waiting for games to download. However, one might have encountered that it went black screen when you check in 15-30 mins, and downloads wasn't going.
The reason is that Gnome decided to suspend your system. This cannot be set from the Steam interface, and needs to be done on the Desktop environment. Just go to Settings -> Power and disable "Automatic Suspend".
Related link: https://discussion.fedoraproject.org/t/gnome-suspends-after-15-minutes-of-user-inactivity-even-on-ac-power/79801
(P.S. This one had me scratching my head until I see that "Gnome is suspending the system" pop up while Steam was downloading games.)
