42beta: moving mouse as screen is fading to screensaver prevents input to shell

[Matthew Ruffell]

[Impact]

If you move the mouse as the system fades into black for the screensaver, the screensaver will be prevented as normal, but the user will not be able to interact with the shell.

Mouse clicks are ignored, and most key presses are ignored too.

Workaround is to press super to enter shell overview, then super again to close, and mouse clicks will begin working again.

gnome-shell 42~beta-1ubuntu2 from -proposed.

[Testcase]

1) Leave your system idle, until the screen starts fading to black
2) As the screen is fading to black, move the mouse to prevent screensaver.
3) Attempt to click any window or type something

[Daniel van Vugt (vanvugt)]

See also bug 1181666, although that's probably a different issue if it is still an issue at all.

[Sebastien Bacher (seb128)]

Do you use x11 or wayland session? Could you add your journalctl log after seeing the issue?

[Matthew Ruffell (mruffell)]

I use the wayland session. I have recorded a short screencast of reproducing the issue. I went gnome settings > power > screen blank > 1 minute to speed it up.

The screencast has journalctl -f running, and there is no output. Interestingly, after enough clicks it seemed to start working again.

Screencast fades to black at 1:13, then I move the mouse and start clicking on icons.

[Launchpad Janitor (janitor)]

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

[Daniel van Vugt (vanvugt)]

I'm starting to think this might be related to bug 1965085. Although pressing Tab works there, but doesn't work here.

[Matthew Ruffell (mruffell)]

Hi Daniel,

I built "clutter: Mark clutter_stage_grab() return value as transfer full" from https://gitlab.gnome.org/GNOME/mutter/-/issues/2189 into mutter 42~beta-1ubuntu2 in a ppa and installed it.

I rebooted, and changed back to 1 minute fade time, and reproduced the issue, so that particular issue is unrelated.

Would you like me to build mutter master branch or another component and try? I was going to try GNOME OS, but there was no live media, and it was install only, and I can't reproduce inside KVM (it never fades to black in virt-manager).

[Daniel van Vugt (vanvugt)]

I should have removed that comment because the code change is not what I thought. Not related to this.

[Till Kamppeter (till-kamppeter)]

If this situation occurs for me and I press ALT + TAB then, I get back to normal and can use mouse and keyboard as usual again.

[Matthew Ruffell (mruffell)]

Hi Daniel,

I installed gnome-shell 42.0-1ubuntu1 from -proposed, along with mutter and others this morning and rebooted. I am no longer able to reproduce this issue, I can move the mouse as the screen is fading, and I can click things and enter text as normal.

I will close the bug in a couple of days if I don't see it again, but I think it has been fixed.

[Daniel van Vugt (vanvugt)]

Great!

I was hoping that 42.0 would fix some of the grab-related bugs.

[Jeremy Bícha (jbicha)]

I'm closing this issue since gnome-shell 42.0-1ubuntu1 has migrated out of proposed.