On the EndeavourOS installed on my laptop, in the power management settings, the screen is set to dim after a certain period of inactivity, and after 5 minutes of inactivity, the screen goes dark. The dimming of the screen also works, but the darkening never happens. I also tested it on a desktop computer. I have experienced this with other Linux distributions as well. I turned off the dimming, but left it on so that the screen goes dark when idle, but it didn’t work either. I noticed this because last time during package updates, the machine was suspended after a twenty minute delay, which is also in the settings. What I don’t understand is that if screen dimming and suspend work when idle, why can’t the screen go dark? Is this a Gnome bug or a feature, and does dimming actually mean darkening?
This is expected to work, please file an issue with your distribution.
I tried it in three different distributions (EndeavourOS, MX Linux, Linux Mint) on a desktop and a laptop. The screen dimming works, the screen never goes dark, no matter how much I set the delay time after inactivity in the power management.
Update. I forgot that LightDM doesn’t, but GDM supports the screen saver function… So I replaced the former with the latter, so everything works fine now.