Good night! I can't login through GDM but can via terminal. Also I can't change layout but successfully do it via terminal.
This is example of /var/log/messages endline:
gdm-simple-greeter[...]: Couldn't enumerate devices
...the permission of the setuid helper is not correct...
And this "permission of the setuid" is everywhere in GDM logs. What the problem is?
Apologies for just posting links but I cannot reproduce the problem myself. I hope this is useful none the less.
There is a thread on this problem on ubuntuforums.org
The solution there was
Another thread suggests the following command may also work