xfce4-screensaver blocks UI on hyper-v

[Daniel]

I have a VM running in hyper-v (on Windows 10, a desktop).

My system is a xubuntu, which means with xfce as standard window manager. It was previously running on xubuntu 18.04, but now, after upgrading to 20.04, the UI "freezes" every time after a few minutes.

Using a text VT, I found that it's the process xfce4-screensaver which I have to kill to be able to continue my work. After killing, everyting works fine.

It seems that under this environment, the screensaver blocks inputs (I guess for security reasons), but fails to paint anything on the screen which should now show a screensaver or blank. I don't see any text field for entering a password or similar, like I do on other installations which are not in a VM.

I recognized some changes also on these other (non-virtualized) systems, they started now to ask for a password which they didn't on 18.04. So I can only guess that something on this mechanism is shaky.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xfce4-screensaver 0.1.10-0ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34
Uname: Linux 5.4.0-31-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Fri May 22 11:19:15 2020
SourcePackage: xfce4-screensaver
UpgradeStatus: Upgraded to focal on 2020-05-20 (2 days ago)

[championchap (championchap)]

This is also effecting me. On a completely up to date 20.04 on real hardware my UI freezes up after a minute or so.
It is strange though, I find that if I right click the desktop it unsticks me for a moment.
It would often show me the lock screen login prompt after it got unstuck.

What seems to have "solved" it for me for the moment is I have disabled both my screensaver and the lock screen in the screensaver settings. It didn't work if I just disabled the screensaver.

Disabling the Lock Screen was annoying to do too, as every time I opened that tab the UI for the contents of that tab would become completely unresponsive. I was still able to switch tabs. Eventually I got it unstuck, though I'm not sure how, and was able to flip the switch.

Very annoying problem.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Oliver Salzburg (oliver-salzburg)]

I also experience this issue in XUbuntu 22.04 on Hyper-V Windows 10 21H2. This is very unexpected and frustrating, because it's unclear that it is the screensaver causing this.

[Zoltan (zoltanuk)]

I am having the same problem Oliver Salzburg had.
Ubuntu is unresponsive even for remote reboot.
Hyper-V needs to be terminated to restart Ubuntu.