Wayland: Image of mouse cursor left on screen after unlock

[Vance Briggs]

Gnome 3 desktop
Multi-monitor setup with one screen rotated right into portrait mode
*Experimental* fractional scaling on Wayland with different scaling on each monitor. Configured using:

~~~
gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"
~~~

After wake from screen lock I often observe an "image" of an enlarged rotated mouse pointer on the second (rotated) monitor which doesn't move and doesn't appear on a screenshot. It overlays all other screen in formation and cannot be erased by moving the mouse over the area. Depending on where the mouse cursor was when sleeping it seems to appear in one of two places, either towards the bottom left or top right. After some time a block around the cursor image gets "corrupted".

This behaviour is not observed if logging in to a X11 session

Because this doesn't show up on a screenshot I have included a photo, which also shows the monitor setup.

Description: Ubuntu 19.04
Release: 19.04

mutter:
  Installed: 3.32.2+git20190711-2ubuntu1~19.04.1
  Candidate: 3.32.2+git20190711-2ubuntu1~19.04.1
  Version table:
 *** 3.32.2+git20190711-2ubuntu1~19.04.1 500
        500 http://gb.archive.ubuntu.com/ubuntu disco-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     3.32.0+git20190410-1ubuntu1 500
        500 http://gb.archive.ubuntu.com/ubuntu disco/main amd64 Packages
---
ProblemType: Bug
ApportVersion: 2.20.10-0ubuntu27.1
Architecture: amd64
CurrentDesktop: GNOME
DistroRelease: Ubuntu 19.04
InstallationDate: Installed on 2019-03-08 (178 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
Package: mutter 3.32.2+git20190711-2ubuntu1~19.04.1
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 5.0.0-27.28-generic 5.0.21
Tags: wayland-session disco
Uname: Linux 5.0.0-27-generic x86_64
UpgradeStatus: Upgraded to disco on 2019-04-21 (134 days ago)
UserGroups: adbusers adm cdrom dialout dip lpadmin plugdev sambashare sudo
_MarkForUpload: True

[Daniel van Vugt (vanvugt)]

Sounds like bug 1724977, but we claim to have fixed that(?).

also...

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1841894

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Vance Briggs (vanceb)]

It's not quite the same as bug 1724977. This doesn't happen when moving the cursor live, but the second copy "appears" after waking from screen lock. My guess is that the lock screen doesn't use the same video memory config as the desktop, but somehow they "overlap" and the cursor gets left over as you log back in from the lock screen.

* The fact that the fake cursor image is large makes me think that it isn't using the same scaling
* The fact that the fake cursor image is rotated (as if the screen is in normal landscape) makes me think that the lock screen is unaware of the desktop screen rotation.

Both of these points may affect the video memory layout which will therefore be different between the desktop and the lock screen...

Currently away from the machine, but I will do the apport-collect next week.

[Vance Briggs (vanceb)]

apport information

[Vance Briggs (vanceb)]

apport information

[Vance Briggs (vanceb)]

apport information

[Andreas Jonsson (andjons)]

I'm on Fedora 30 and also experiencing this. Dual monitors (one rotated, portrait right) on Wayland, but not using any scaling. Happens every time when waking up from sleep. AMD Vega 56 graphics card. Bug report (not by me) on Red Hat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1745055

[Vance Briggs (vanceb)]

Does this video help give more clues about the issue. You can see the "Fake cursor" icon changing in line with the realk cursor, but the fake cursor isn't moving

[Launchpad Janitor (janitor)]

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

[David Krauser (davidkrauser)]

I'm seeing very similar behavior on Ubuntu 19.10 with X11 and a single monitor:

I've noticed on Ubuntu 19.10 with X11 fractional scaling set to 1.25x, the pointer duplicates itself when I login to a new session. The original pointer sticks on the screen at 1x size, and I get a new pointer to use that's scaled for the 1.25x session. The new pointer follows the mouse, but the original pointer is stationary.

If I disable/re-enable fractional scaling in the same session, the duplicate pointer disappears.

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 19.04 (disco) reached end-of-life on January 23, 2020.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.

[Daniel van Vugt (vanvugt)]

David,

Please open a new bug by running:

  ubuntu-bug mutter

[Joel Lisenby (sven-svenagen)]

Same issue happening to me, was happening on 19.10 and still continues after upgrading to 20.04 today.

Logging out and back in again resets/hides the extra "dead" cursor, but it appears again after locking the screen and the monitors go to sleep.

[Daniel van Vugt (vanvugt)]

^^^
Bug 1875528

[Danny (fredhair)]

I'm experiencing the same issue in 20.04, dual monitor setup, fractional scaling using the default wayland on gnome 3.36.4. I have a vega 56 and use the amdgpu drivers. If I leave the ghost cursor and get on with something else it will eventually change to a square of random brightly coloured pixels overlaid (doesn't show on printscreen). It's as if there's a dodgy block of vram where the display memory is. Logging out and back in solves the issue until my screen locks again.

[Mr.Gosh (mr-gosh)]

Similar but without the fractional scaling:
https://bugs.launchpad.net/bugs/1950428