r/NixOS • u/Stunning-Mix492 • 1d ago
Stuck on blinking cursor on boot
Hi,
My last update on nixos failed. I use a simple gnome setup with flakes, pointing to the 26.05 stable release. With last update, After boot splash, I'm stuck on a blinking cursor, GDM does not launch. I can switch to another virtual terminal, reboot the machine, and boot on the last functional generations (thank you nixos!). But I don't know how to investigate the problem. I think it may be related to the last systemd update. Anyone experience the same problem? Any fix found?
My last functional generation was generated with "nh os boot --update" yesterday.
Solved: do not use unstable mesa on stable release :)
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u/Quietus87 1d ago
It would he helpful if you shared your hardware, config files, or logs.
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u/Stunning-Mix492 1d ago
hw: LENOVO 21RV0019FR/21RV0019FR, BIOS R2XET41W (1.21 ) 07/31/2026
my config files are way too complex to post here (multiple files for multiple machines with common flakes parts, etc.)
I'll try to post a journalctl -b output of the "gdm not starting" situation
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u/Quietus87 1d ago
Why don't you keep them in a github repo?
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u/Stunning-Mix492 1d ago
they are, but private
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u/DaymanTargaryen 1d ago
Maybe share them publicly? It's hard to diagnose issues without seeing the configuration.
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u/Stunning-Mix492 1d ago
found something interesting. While gdm seems blocked, trying to restart it gives:
Failed to restart gdm.service: Unit gdm.service is masked.weird
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u/Stunning-Mix492 1d ago
gdm seems to be very suspect:
● display-manager.service - Display Manager Loaded: loaded (/etc/systemd/system/display-manager.service; linked; preset: ignored) Active: active (running) since Thu 2026-10-01 21:20:32 +04; 1min 14s ago Invocation: 6098209b60a8439585cc9ec73689e9ec Main PID: 1999 (gdm) IP: 0B in, 0B out IO: 6.1M read, 0B written Tasks: 4 (limit: 66953) Memory: 6.7M (peak: 12M) CPU: 129ms CGroup: /system.slice/display-manager.service └─1999 /nix/store/g1ykf46ng2slmdpj914sn3hs6kqbm5xi-gdm-50.2/bin/gdm oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: Child process -2418 was already dead. oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: GdmDisplay: Session never registered, failing oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: Child process -2418 was already dead. oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: GdmDisplay: Session never registered, failing oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: Child process -2505 was already dead. oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: GdmDisplay: Session never registered, failing oct. 01 21:20:34 ouroboros gdm[1999]: Gdm: Child process -2505 was already dead. oct. 01 21:20:35 ouroboros gdm[1999]: Gdm: GdmDisplay: Session never registered, failing oct. 01 21:20:35 ouroboros gdm[1999]: Gdm: GdmLocalDisplayFactory: maximum number of display failures reached. Giving up. oct. 01 21:20:35 ouroboros gdm[1999]: Gdm: Child process -2585 was already dead.
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u/Boatetye 1d ago
Having the same problem on unstable. I've just booted into the previous generation for now. If you have Plymouth enabled you could try disabling it or lower consoleLogLevel to show more debug information.