3 displays not working under Gnome/Wayland since latest mutter version

Hi everybody,

I’ve been using my ThinkPad T480s with the UltraDock with 2 external monitors and the integrated display since I’m using EndeavorOS. Desktop environment is Gnome with Wayland.
Since the update on 18.04.2021, this does not work any more. After enabling the 3rd display, the external displays turn black.

After some investigation I believe that maybe the update of mutter to 40.0+55+gf4f82bcb9-1 is the problem. I reverted the updates via the Arch Archive to the 18.04. Now everyhing works again.

Currently there are the following updates outstanding:

Packages (78) alsa-card-profiles-1:0.3.26-1  arduino-builder-1.5.4-2  avahi-0.8+20+gd1e71b3-1
              chromium-90.0.4430.85-1  cifs-utils-6.13-2  cups-1:2.3.3op2-3  dbus-glib-0.112-1
              electron-12.0.5-1  firefox-88.0-1  gedit-40.1-1  gjs-2:1.68.0-3
              glib-networking-1:2.68.1-1  gnome-online-accounts-3.40.0-1
              gnome-shell-1:40.0+39+gd9e953e93-1  graphicsmagick-1.3.36-2
              gst-plugin-pipewire-1:0.3.26-1  gtk3-1:3.24.29-1  guile-2.2.7-1  hwinfo-21.73-1
              hwloc-2.4.1-1  imagemagick-  js78-78.10.0-1  less-1:581-1
              lib32-libgpg-error-1.42-1  lib32-mesa-21.0.3-1  lib32-vulkan-intel-21.0.3-1
              libcups-1:2.3.3op2-3  libdvdcss-1.4.3-1  libdvdnav-6.1.1-1  libdvdread-6.1.2-1
              libgcrypt-1.9.3-1  libglvnd-1.3.2-2  libical-3.0.10-1  libjpeg-turbo-2.1.0-1
              libluv-1.41.0-1  libmm-glib-1.16.4-1  libnm-1.30.4-1  libteam-1.31-3  libtiff-4.3.0-1
              libupnp-1.14.6-1  libxdg-basedir-1.2.3-1  linux-5.11.16.arch1-1
              linux-headers-5.11.16.arch1-1  mesa-21.0.3-2  mlocate-0.26.git.20170220-7
              modemmanager-1.16.4-1  mutter-40.0+55+gf4f82bcb9-1  networkmanager-1.30.4-1
              nextcloud-client-3.2.0-1  ngspice-34-1  nodejs-16.0.0-1  npm-7.11.1-1
              openssh-8.6p1-1  pacman-5.2.2-3  perl-xml-libxml-2.0207-1  pipewire-1:0.3.26-1
              pipewire-media-session-1:0.3.26-1  protobuf-3.15.8-1  python-3.9.4-1
              python-importlib-metadata-4.0.1-1  python-setuptools-1:56.0.0-1  python-urwid-2.1.2-1
              python-yaml-  qt5-base-5.15.2+kde+r180-1  qt5ct-1.2-1  r8168-8.048.03-88
              smbclient-4.14.3-1  sqlite-3.35.5-1  thunderbird-78.10.0-1  vtk-8.2.0-18
              vulkan-headers-1:1.2.176-1  vulkan-intel-21.0.3-2  welcome-3.12.4-1  wildmidi-0.4.4-1
              wireshark-cli-3.4.5-1  wireshark-qt-3.4.5-1  wvstreams-4.6.1-17  xmlsec-1.2.32-1

In the logs I looked at (journal etc.) were no obvious errors.

Anybody with the same Problems ? Some hint how to find the error ?

It appears that you have already found the package that caused the problem, so check its known bugs. For example: https://bugs.archlinux.org/task/70511

Did you update everything, or only Mutter, when you found a problem?

I’ve searched the mutter bug tracker but overlooked the arch tracker …
Thanks for the hint. Did you find the bug in the mutter bug tracker ?

There were multiple updates, so I reverted all of them. Maybe I can update all except gnome-shell and mutter. This should give a clear view on the packages causing the problem.