Arch Linux

Bendilock

Member

Registered: 2021-01-21

Posts: 10

[SOLVED] Screen goes black after login to LightDM

Hi!

Yesterday I fell asleep in front of my laptop and when I woke up my screen was black. There was still sound playing. I rebooted and I come to the login screen (lightdm-gtk-greeter), everything is still fine, but after I enter my credentials, the screen almost immediately turns black, and I don't see my mouse. However, I can open up a terminal (I don't see the terminal, but I can enter commands, like "sudo reboot" or "sudo shutdown now", and they execute). This behavior is consistent. I've tried logging in over 10 times now and it's the same thing.

I updated my system maybe 1 week before that, and have been using the laptop after that, so a software update shouldn't be the cause. Anyway, at the login screen, I switched to another tty with "CTRL + ALT + F2" and updated my system with "pacman -Syu", but that didn't help.

After logging in and getting the black screen, I can still switch to another tty, but I can't see any text. But I can run "sudo shutdown now" in the dark, and it executes.

Switching to another tty, I have run "systemctl status lightdm", and I see that it is running.

Running "journalctl -r -u lightdm" does not seem to output any problems:

journalctl -r -u lightdm
Aug 19 11:35:05 garch lightdm[433] pam_unix(lightdm-greeter:session): session opened for user lightdm(uid=972) by (uid=0)
Aug 19 11:35:03 garch systemd[1]: Started Light Display Manager.
Aug 19 11:35:03 garch systemd[1]: Starting Light Display Manager...

I installed arch a month ago using the `archinstall` guided installation, choosing the MATE desktop environment.

It's a 7 year old HP laptop with no Nvidia graphics or anything, just integrated Intel graphics.

I saw this in the Arch Wiki: https://wiki.archlinux.org/title/Intel_ … figuration but I haven't tried that yet. Should I do that? Anyone else have an idea what could be wrong, or some output I could check?

Thanks in advance!

Last edited by Bendilock (2023-08-19 14:58:31)

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,112

Re: [SOLVED] Screen goes black after login to LightDM

Login w/ lightdm, switch to another TTY (ctrl+alt+f2)

DISPLAY=:0 xrandr -q | curl -F 'f:1=<-' ix.io

Post the url you get (or just look at the xrandr output and probably activate the relevant monitor)

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

Bendilock

Member

Registered: 2021-01-21

Posts: 10

Re: [SOLVED] Screen goes black after login to LightDM

If I run that before logging in, it says

DISPLAY=:0 xrandr -q | curl -F 'f:1=<-' ix.io
Authorization required, but no authorization protocol specified

Can't open display :0

If I log in and quickly switch back to the other tty, then I managed to get this output: http://ix.io/4DxW

But I have to be very quick, because 1 second after entering my credentials, the screen goes black, including all other ttys.

This is a laptop with only 1 screen, and I've never had another monitor hooked up to it.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,112

Re: [SOLVED] Screen goes black after login to LightDM

That link is some python hello world, but

screen goes black, including all other ttys

sounds more like a backlight issue anyway?
https://wiki.archlinux.org/title/Backlight

Can you ssh into the system?

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

Bendilock

Member

Registered: 2021-01-21

Posts: 10

Re: [SOLVED] Screen goes black after login to LightDM

Oh my god you were right. OH MY GOD I feel so stupid. Thank you so much!!!