Prevent XScreenSaver from flashing unlocked screen

[yuri69]

Hi,
I've been using x11-misc/xscreensaver for a while on my laptop. It's fast and seems to be a bit more secure than the rest of common screen lock apps. But there is one thing...

I simply can't configure it well enough to prevent it from showing the unlocked screen for a very brief period (500ms?) before it shows the lock screen itself. This happens after I wake the laptop up from sleep but it doesn't occur every time - it's like 50:50.

The setup is systemd + i3wm with the screensaver being started by auto-running:

[Hu]

This is an inherent problem with a screensaver / screenlocker that is not integrated in the rendering path. At the time you enter suspend, you were recently active, so the screen is correctly not blanked. When you resume, your X server is restored and begins rendering to the screen, showing whatever you had open. Soon afterward, but not instantly, the kernel will get around to scheduling xscreensaver, which will notice that the current time says you have been idle for hours, and will react by blanking / locking the screen. As you observed, this may or may not be fast enough to happen before Xorg renders to the monitor. The typical solution to this is that you need to run xscreensaver-command -lock on the suspend path, so that the screen is already blanked and locked before you enter suspend, and is still that way when you resume.

[yuri69]

[Hu]

Yes, that mechanism is intended to address this issue. It's optional though, and it did not occur to me to check whether you were using it. If you run that command manually, does it consistently blank the screen before the shell prompt returns? I speculate, with no data to support this, that the screen blanking may initiate immediately, but not finish before the system enters suspend.

[yuri69]