> That is impossible on Gnome. You get a dropdown of a few fixed values, none greater than 60 minutes, and you better like what choices the Gnome devs have granted you. The workaround requires some brain surgery in the terminal.

AFAIK what gnome does is not give you any options above 15 minutes, but they do provide a toggle for disabling screen power saving and toggles for other such power saving features.

I've always been able to disable if fine, what irks me is the artificial 15 minutes limit in the drop down menu, forcing you to edit dconf entries to increase it...