GNOME/GDM Login Loop after update (Radeon GPU) - Manual gnome-shell works, GDM/LightDM fails

[regemaster]

Hi everyone,

I’m struggling with a persistent login issue on Manjaro (GNOME, Radeon GPU) after a recent system update. I’ve tried several troubleshooting steps, but I’m stuck in a “Login Loop” or a blank GDM screen.

The Problem:

• GDM: Shows a gray screen with the top bar (clock/icons), but the login prompt never appears.
• LightDM: (Installed for testing) Shows the login screen, but after entering credentials, it flashes black and returns to the login screen (Login Loop).
• Interesting Fact: If I switch to TTY and run gnome-shell, the desktop environment starts and works correctly. However, running dbus-run-session gnome-shell fails with an error.

What I’ve Done So Far:

1. Drivers/KMS: Verified Radeon (Mesa) drivers. Added amdgpu to MODULES in /etc/mkinitcpio.conf and ran mkinitcpio -P. No change.
2. Sessions: Discovered that /usr/share/xsessions was missing. Reinstalled gnome-session, gnome-shell, and manually recreated session files.
3. Config: Tested both WaylandEnable=false and true in /etc/gdm/custom.conf.
4. Permissions: Checked ~/.Xauthority and ran chown -R $USER:$USER on my home directory.
5. New User: Created a fresh test user – the same login loop occurs, so it’s not a local config issue in my home folder.
6. Reinstalls: Reinstalled gdm, gnome-shell, and video-linux (via mhwd).

Current Status:

It seems like the graphics stack is fine, but there’s a breakdown in communication between the Display Manager and D-Bus/User Session. The system “lives,” but the session initialization fails.

System Info:

• OS: Manjaro
• DE: GNOME
• GPU: Radeon (using open-source drivers)

Does anyone have insights into why dbus-run-session might be failing or why GDM/LightDM cannot hand over the session to GNOME even though the shell itself can run manually?

Any help would be greatly appreciated!

[soundofthunder]

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