Fedora 42 hangs after ~15 min idle when external display connected via USB-C

[computersavvy (Jeff V)]

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GNOME suspends after 15 minutes of user inactivity, even on AC power

Problem Since Fedora 38, systems with the GNOME desktop environment suspend after 15 minutes of user inactivity, even when plugged in to the AC outlet. This affects new installs and some upgraded systems (depending whether you touched that setting in the past). This is due to an intentional change. To give it a better visibility, and because it might surprise many users and consider it a bug, it’s documented here. Note: Remote sessions might not be considered when GNOME tracks user activity. G…