This bug was fixed in the package gdm3 - 49~rc-0ubuntu1
---------------
gdm3 (49~rc-0ubuntu1) questing; urgency=medium
* New upstream release:
- Fix greeter starting before a GPU driver has loaded (LP: #2115451)
* debian: Restore support for logging into X11 sessions
- This also restores support for running the greeter in X11 mode,
because the two couldn't be decoupled in time for GNOME 49.
* d/rules: Restore working-dir meson option
* d/p: Refresh patches
-- Alessandro Astone <[email protected]> Thu, 04 Sep
2025 12:00:40 +0200
** Changed in: gdm3 (Ubuntu Questing)
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/2115451
Title:
Since kernel 6.9, the login screen starts with simpledrm and switches
to amdgpu one second later, causing freezes
Status in gdm3 package in Ubuntu:
Fix Released
Status in linux package in Ubuntu:
Won't Fix
Status in gdm3 source package in Noble:
Triaged
Status in linux source package in Noble:
Invalid
Status in gdm3 source package in Plucky:
In Progress
Status in linux source package in Plucky:
Won't Fix
Status in gdm3 source package in Questing:
Fix Released
Status in linux source package in Questing:
Won't Fix
Bug description:
[ Impact ]
Since around about kernel 6.9, gdm3 fails to wait for a proper DRM
kernel driver to load. So if your kernel driver is particularly slow
(like dual AMD GPU systems in this case) then the login screen is
displayed using simpledrm and software rendering. That wouldn't be a
problem by itself except that a second or two later, the kernel
"hotplugs" the old graphics card out and replaces it with the proper
one. Mutter/GNOME currently cannot handle GPU hotplugging well and
will usually freeze.
[ Test Plan ]
Ideally this should be executed by someone who experienced the issue
in the first place (dual AMD GPU machines). Otherwise the login
process should just be verified for robustness and the steps are the
same:
1. Reboot the machine.
2. Expect the login screen to appear.
3. Log in immediately.
4. Expect the desktop appears.
5. Press Super or Super+A and expect the screen to animate.
6. Reboot the machine again.
7. Expect the login screen to appear.
8. Wait at least 20 seconds before logging in.
9. Expect the desktop appears.
10. Press Super or Super+A and expect the screen to animate.
[ Where problems could occur ]
Since the loop gating the start of the login screen itself is being
modified, there is a risk that some part of the login experience could
become broken or delayed.
[ Other Info ]
This issue likely affects more than just the two people who reported
it here because we're not counting anyone else who experiences a
frozen login screen and just didn't report the bug in enough detail.
[ Original Description ]
After upgrading to Ubuntu 25.04 my laptop fails to properly start the
gnome login shell. During boot I see the graphical splash screen as
expected, but once the login screen should show, one of the below
things happen:
- Nothing, I keep seeing the boot splash screen.
- The login screen is rendered, but only a single frame. Moving the mouse or
pressing keys has no effect.
- The login screen is rendered and the mouse cursor moves, but none of the
widgets respond to clicks or pressing keys.
To recover, I have to Ctrl+Alt+F2 and login on the terminal interface.
Then I can do a `sudo systemctl restart user-120.slice` after which I
can go back to the GUI login screen and it works.
ProblemType: Bug
DistroRelease: Ubuntu 25.04
Package: gnome-shell 48.0-1ubuntu1
ProcVersionSignature: Ubuntu 6.14.0-22.22-generic 6.14.5
Uname: Linux 6.14.0-22-generic x86_64
ApportVersion: 2.32.0-0ubuntu5.2
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu Jun 26 22:21:40 2025
DisplayManager: gdm3
InstallationDate: Installed on 2024-12-25 (183 days ago)
InstallationMedia: Ubuntu 24.10 "Oracular Oriole" - Release amd64 (20241009.4)
RelatedPackageVersions: mutter-common 48.1-1ubuntu3
SourcePackage: gnome-shell
UpgradeStatus: Upgraded to plucky on 2025-06-15 (11 days ago)
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