I don't know when this "feature" slipped into Fedora (and CentOS). Not long ago (weeks, few months) I recall not needing to provide a password to restore the desktop when resuming from suspend to RAM. Now I do.

I use the lightdm login manager and MATE desktop. I do not know whether that is related.

Lock screen when using the screen saver is disabled.

Any ideas about the cause?

Thanks.

Edit: Related, I am unable to invoke suspend at the login manager. Closing the lid or pressing Fn+F4 results in no action -- until I log in. Then after the desktop startup completes the systems goes into suspend mode.

I don't know about Fedora, but in most distros this is a configurable setting. I also don't know about Mate, but it's probably a setting there. In Debian Xfce, there is a checkbox to turn on/off "Lock screen when system is going for sleep". The lock screen requires a password to unlock. That's also configurable in many DEs.

While it will be different than with KDE it could help. In KDE you need to look in the system settings panel / power management / advanced settings there is a checkbox "lock screen on resume" which is enabled by default.

If your desktop stores settings in some directory with a dot or otherwise you could try to use grep -ir 'resume' *
and see if you see some filename that rings a bell about settings.

Thanks. Makes sense except I find no similar configuration option in MATE. I restored a Fedora 21 backup to a testing partition. Using the same user profile and MATE profile, I did not have to provide a password. While inconclusive this would seem to point to a system-wide setting rather than user.

Edit: Looks system related. I installed the F22 MATE spin. No requirement to type a password. After updating with dnf I now have to type a password when resuming from suspend.

The problem is caused by the latest mate-screensaver package. Deleting the package or reverting to a previous version eliminates the problem.

There seem to be two related dconf options but no obvious GUI control. Playing with the dconf options (lock-suspend and lock-use-screensaver) makes no difference.