Arch Linux

ksldmitriy

Member

Registered: 2025-09-27

Posts: 2

[SOLVED] Black screen with an underscore after update.

Hi everyone,
After I updated the system, I get a black screen with a blinking underscore instead of the GDM login screen. I’ve tried every solution I could find online, but nothing worked.

My setup:
kernel: linux-lts
GPU: Nvidia RTX 4070 super

/etc/mkinitcpio.conf: https://0x0.st/Kav9.txt

/etc/modprobe.d/nvidia.conf:

options nvidia_drm modeset=1 fbdev=0
blacklist nouveau

lsmod | grep nvidia:

nvidia_uvm           3874816  0
nvidia_drm            143360  0
nvidia_modeset       1851392  1 nvidia_drm
drm_ttm_helper         16384  1 nvidia_drm
video                  81920  1 nvidia_modeset
nvidia              111460352  2 nvidia_uvm,nvidia_modeset

systemctl status gdm.service:

● gdm.service - GNOME Display Manager
     Loaded: loaded (/usr/lib/systemd/system/gdm.service; enabled; preset: disabled)
     Active: active (running) since Sat 2025-09-27 14:14:33 EEST; 2h 47min left
 Invocation: 43fdb8aedbc247dbbe09a5ac8bcec14c
   Main PID: 668 (gdm)
      Tasks: 5 (limit: 38012)
     Memory: 4.5M (peak: 7.3M)
        CPU: 168ms
     CGroup: /system.slice/gdm.service
             └─668 /usr/bin/gdm

Sep 27 14:14:54 archlinux gdm[668]: Gdm: Child process -1628 was already dead.
Sep 27 14:14:54 archlinux gdm[668]: Gdm: GdmDisplay: Session never registered, failing
Sep 27 14:14:54 archlinux gdm[668]: Gdm: Child process -1628 was already dead.
Sep 27 14:14:55 archlinux gdm[668]: Gdm: GdmDisplay: Session never registered, failing
Sep 27 14:14:55 archlinux gdm[668]: Gdm: Child process -1698 was already dead.
Sep 27 14:14:55 archlinux gdm[668]: Gdm: GdmDisplay: Session never registered, failing
Sep 27 14:14:55 archlinux gdm[668]: Gdm: Child process -1698 was already dead.
Sep 27 14:14:56 archlinux gdm[668]: Gdm: GdmDisplay: Session never registered, failing
Sep 27 14:14:56 archlinux gdm[668]: Gdm: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors
Sep 27 14:14:56 archlinux gdm[668]: Gdm: Child process -1766 was already dead.

xrandr:

Can't open display

How can i fix it?

Thanks for your help!

EDIT:
Solution: Set UseWayland to true in gdm config.

Last edited by ksldmitriy (2025-09-30 11:51:44)

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,150

Re: [SOLVED] Black screen with an underscore after update.

Sep 27 14:14:56 archlinux gdm[668]: Gdm: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors

GDM on X11 doesn't work any longer, if this isn't deliberate and a botched fallback attempt from an also failed wayland start, see https://bbs.archlinux.org/viewtopic.php?id=308372&p=4

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ksldmitriy

Member

Registered: 2025-09-27

Posts: 2

Re: [SOLVED] Black screen with an underscore after update.

Changed UseWayland=false to UseWayland=true in gdm config and that fixed it.

Thank you so much!

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,150

Re: [SOLVED] Black screen with an underscore after update.

\o/
Please always remember to mark resolved threads by editing your initial posts subject - so others will know that there's no task left, but maybe a solution to find.
Thanks.

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc