My system crashed today (it closed all programs and the session but did not reboot). I then did un update before rebooting.
Since then, the system is not going to sleep from the lock screen: every few minutes (intervals can vary), the system emit a sound and the screen turns on with the lock screen, then the screen goes black again, then a noise and the screen wakes up etc…
In the logs, there is an error:
15:56:47 systemd: Failed to start systemd-suspend.service - System Suspend.
15:56:47 systemd-sleep: Failed to put system to sleep. System resumed again: Device or resource busy
15:56:47 kernel: Freezing user space processes failed after 20.008 seconds (1 tasks refusing to freeze, wq_busy=0):
The system can go to sleep if I force it to go via the menu