Why suspend in 19.04 takes 30 seconds?

This question seems to have been asked in different forms, but I have not yet found a real solution! I thought that it might be useful to explain exactly what is happening on my system under Ubuntu 19.04 in case this could shed further light on the problem …

I've tried various methods to suspend my system, including:

1) Third-party extension of Gnome "Hang Button"
2) Hold down the Alt key to force the Power Off button to become a suspend key.
3) Assigning a keyboard shortcut to the "/ bin / systemctl suspend" command
4) Tap the power button on the desktop

In cases 1-3:

  • The screen is white IMMEDIATELY and stays blank for about 2 seconds.
  • The screen will empty and return to the state it was in before trying to suspend.
  • As long as the screen is not empty, the system is active and can be used.
  • Exactly 30 seconds after the launch of the "suspend", the screen goes back to black AND the system goes into suspend mode.

In case 4, the screen immediately clears and the system goes into standby mode immediately.

This problem is not a real problem because I can press the shortcut key as shown in case 3 above, and then exit the system. It would be a little more satisfying, though, if the "suspension" was taking place immediately instead of being delayed by 30 seconds!

Any suggestions / thoughts would be greatly appreciated!