gdm3 fails to start after upgrading.  I get the black screen with a blinking
cursor in the top left corner.

The problem happens when upgrading the following:
gdm3 48.0-3 to 49.1-6
gir1.2-gdm-1.0 48.0-3 to 49.1-6
libgdm1 48.0-3 to 49.1-6
gnome-session 48.0-2 to 49.1-3
gnome-session-bin 48.0-2 to 49.1-3
gnome-session-common 48.0-2 to 49.1-3

This is the smallest set of dependent packages I can narrow it down to.
gdm3 starts fine when I revert the upgrade.

Control: tags -1 + moreinfo
successfully for others. Please check the systemd Journal for log
messages that occur during the failed startup.

This doesn't look like an official Debian kernel, so one possible cause
is if your (presumably locally-built) kernel doesn't support a required
feature.

Is that proprietary/out-of-tree module a version of the Nvidia
proprietary driver?  If yes, what version?

GNOME 49 only supports Wayland sessions. gdm3 can still launch X11
sessions as the session you log in to (tested with cinnamon), but the
gdm3 greeter (the login prompt) is now always a Wayland session, and so
is a GNOME login session.

     smcv

Including the journal for the failed boot using the official debian
kernel 6.12.48+deb13-amd64. journalctl.txt

Tried using debian official kernel 6.12.48+deb13-amd64.  Did not make
any difference.

Yes it is the proprietary nvidia module version 550.163.01-3
The journalctl.txt included is with WaylandEnable=false

journalctl_new.txt is with WaylandEnable=false commented out.
This got a little farther as gdm actually started and let me attempt to
login.  After entering userid and password I got a blank screen and the
screen came back to the login screen.  If I try to login again it said
someone was already logged in.  Gnome never starts.

On Fri, 14 Nov 2025 19:31:58 -0600 "Brent S. Elmer, Ph.D." <webe3vt@aim.com> wrote:

I was experiencing the same issue, using everyone's favorite graphics
drivers (Nvidia) and followed the steps in
https://wiki.debian.org/NvidiaGraphicsDrivers#wayland-modesetting to
get Wayland and my desktop working again. I recommend you try the same
to see if this bug should stay open.

This bug also affects me.

Regards,

larryw3i

I finally had some time to experiment.  I already had nvidia-
drm.modeset=1 on my grub command line.  I commented WaylandEnable=false
in /etc/gdm3/daemon.conf.
I have 2 4k monitors.  I have scaling set to 100% on both monitors and
font scaling to 1.70 in gnome tweaks.

Here are the issues I have with gnome under wayland.
1. When I log in to gnome, only one of the 2 monitors shows up.  It
appears to be random which one it is.  The other one gets no signal. If
the monitor specified as the primary display and I have it set to only
show the top bar and activities on the primary display, I cannot do
much.  I have to right click on the desktop to get to displays.  Both
monitors are marked as being used even though only 1 is showing
anything.  I unmark then apply then mark then apply the monitor that is
not showing.  Then both monitors show up.  By this time, the wrong
monitor shows as primary and I have to fix this also.  This is a major
problem to have to do every time I log in.

2. chromium does not show the min, close icons anymore.  I have to
right click on the chromium title bar to get the min, close options.  I
have found that I can also guess where the icons are and blindly click
them and they work.  This is also not cool.

3. The UI under wayland does not seem as responsive as under xorg
either.

4. When I update to this version of gdm3 and gnome-session, I no longer
have the ability to run gnome under xorg(i.e. the original problem I
reported).  This shows up on the gdm3 select menu as default Xsession
which is what I always used and everything just worked.

A lot of these issues are minor annoyances but the monitor issue is a
major problem for me.