Hi everyone, I'm facing exactly the same issue in GNOME 40. Same symptoms: The screen in the second display is entirely blank, except for the mouse pointer which I can move. I'm not using proprietary nvidia drivers, just Wayland, Nouveau, Mutter, on GNOME 40.
Here's some environmental information: Versions: === $ dpkg -l xserver-xorg-video-nouveau mutter xwayland Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Architecture Description +++-==========================-============-============-=========================================================== ii mutter 40.4-2+b1 amd64 Example window manager using GNOME's window manager library ii xserver-xorg-video-nouveau 1:1.0.17-1 amd64 X.Org X server -- Nouveau display driver ii xwayland 2:1.20.11-1 amd64 Xwayland X server === Devices: === $ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation HD Graphics 630 (rev 04) 01:00.0 VGA compatible controller: NVIDIA Corporation GM107GLM [Quadro M1200 Mobile] (rev a2) === Info from reportbug: === -- System Information: Debian Release: bookworm/sid APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'unstable'), (500, 'testing'), (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 5.14.0-1-amd64 (SMP w/8 CPU threads) Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages mutter depends on: ii adwaita-icon-theme 41.0-1 ii gnome-settings-daemon-common 40.0.1-2 ii gsettings-desktop-schemas 41.0-1 ii libc6 2.32-4 ii libgles2 1.3.4-2+b1 ii libglib2.0-0 2.70.0-1 ii libmutter-8-0 40.4-2+b1 ii libwayland-client0 1.19.0-2 ii libx11-6 2:1.7.2-2+b1 ii libxcomposite1 1:0.4.5-1 ii mutter-common 40.4-2 ii zenity 3.41.0-2 mutter recommends no packages. Versions of packages mutter suggests: ii gnome-control-center 1:40.1-1 ii xdg-user-dirs 0.17-2 -- no debconf information ===