Bug#1120609: gdm3 fails to start after upgrade to 49.1-6

[Dan Chokola]

On Fri, 14 Nov 2025 19:31:58 -0600 "Brent S. Elmer, Ph.D."
<webe3vt at aim.com> wrote:
> On Thu, 2025-11-13 at 09:57 +0000, Simon McVittie wrote:
> > Control: tags -1 + moreinfo
> >
> > On Wed, 12 Nov 2025 at 21:38:29 -0600, Brent wrote:
> > > gdm3 fails to start after upgrading.  I get the black screen with a
> > > blinking
> > > cursor in the top left corner.
> >
> > We will need more information than this: the same upgrade has worked
> > successfully for others. Please check the systemd Journal for log
> > messages that occur during the failed startup.
>
> Including the journal for the failed boot using the official debian
> kernel 6.12.48+deb13-amd64. journalctl.txt
>
>
> > > Kernel: Linux 6.12.48251025 (SMP w/2 CPU threads; PREEMPT)
> > > Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_WARN,
> > > TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
> >
> > 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.
>
> Tried using debian official kernel 6.12.48+deb13-amd64.  Did not make
> any difference.
>
> >
> > Is that proprietary/out-of-tree module a version of the Nvidia
> > proprietary driver?  If yes, what version?
> >
>
> Yes it is the proprietary nvidia module version 550.163.01-3
>
> > > /etc/gdm3/daemon.conf changed:
> > > [daemon]
> > > WaylandEnable=false
> 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.
> >
> > 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

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.

-- 
Dan Chokola