Comment 32 for bug 1054299

(In reply to siukola.antti from comment #0)
> Running XFCE on Xubuntu 13.04 and noticed that suspend + lock screen doesn't
> always work as expected. When I'm suspending the system and the option "Lock
> screen when going for suspend/hibernate" is used, the system seeems to
> suspend normally. However, when waking up the system yet again, I see a
> short glance of the desktop that was on when suspending. Only after that I
> get the lock screen password prompt. This happens randomly, not always.

If I have understood correctly, xfce4-session nowadays waits until xflock4 finishes, before it suspends. The problem was especially with xscreensaver, since it can be configured to fade screen given time and it may slow anyway [1]. However, since current xflock4 runs 'xscreensaver-command -lock' in foreground, it waits until the fading is complete.

[1] https://bugs.launchpad.net/ubuntu/+source/xscreensaver/+bug/1701917