Arch Linux

Andrew__2

Member

Registered: 2023-01-04

Posts: 1

LightDM "Failed to start session" after authenticating w/ greeter

I followed this wiki to install LightDM.

After successfully authenticating with a greeter (I've tried gtk and slick, both display fine but give the same problem) I receive a message "Failed to start session"

These three posts all seemed related to my problem but haven't given me a solution yet.
They did help me find the LightDM log file and lead me to what I think is probably the issue.
https://bbs.archlinux.org/viewtopic.php?id=175980
https://bbs.archlinux.org/viewtopic.php?id=212073
https://bbs.archlinux.org/viewtopic.php?id=258536

Definitely showing just how new I am with this one but... I'm not sure how to get the log file onto this forum without just typing it out, so I didn't include the whole file.
Here is what I assume to be the important part of /var/log/lightdm/lightdm.log

...
[+1.08] DEBUG: Activating VT 7
[+1.08] DEBUG: Activating login1 session c1
[+1.08] DEBUG: Seat seat0 changes active session to c1
[+1.08] DEBUG: Session c1 is already active
[+1.28] DEBUG: Greeter connected version=1.32.0 api=1 resettable=false
[+2.37] DEBUG: Greeter start authentication for andrew
[+2.37] DEBUG: Session pid=545: Started with service 'lightdm', username 'andrew'
[+2.38] DEBUG: Session pid=545: Got 1 message(s) form PAM
[+2.38] DEBUG: Prompt greet with 1 message(s)
[+7.11] DEBUG: Continue authentication
[+7.11] DEBUG: Session pid=545 Authentication complete with return value 0: Success
[+7.11] DEBUG: Authentication restul for user andrew: Success
[+7.11] DEBUG: User andrew authorized
[+7.11] DEBUG: Greeter requests default session
[+7.11] DEBUG: Seat seat0: Failed to find session configuration default
[+7.11] DEBUG: Seat seat0: Can't find session 'default'
[+7.11] DEBUG: Greeter start authentication for andrew
...

When I check for /usr/share/xsessions/default.desktop, which seems to be what LightDM is looking for based on those other posts, the /usr/share/xessesions directory doesn't even exist. I suspect this should have been created by Xorg or LightDM when I installed them or something. But maybe this isn't even the main issue?

Any help is appreciated. Worst case I can just use a different Desktop Manager, but I'd like to at least know why I couldn't get LightDM to work.

Head_on_a_Stick

Member

From: London

Registered: 2014-02-20

Posts: 7,732

Website

Re: LightDM "Failed to start session" after authenticating w/ greeter

Is there a file at ~/.dmrc that has 'Session=default'? If so then remove that file or change the setting.

I'm not sure how to get the log file onto this forum without just typing it out

https://wiki.archlinux.org/title/List_o … ted_client

EDIT: but you really shouldn't bother with LightDM because it runs X under the root user, which is bad.

Last edited by Head_on_a_Stick (2023-01-06 20:05:18)

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Are you infected with Wetiko?