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No more opening session screen

PostPosted: Sat Jul 30, 2016 8:56 am
by speedstream
Hi Guys,

I yesterday did an apt update / apt upgrade.
After that, the next reboot offered me a login screen with a typical ubuntu wallpaper and nothing more. It is just stuck there and does nothing.

I did installed Ultimate Edition 5.0 XFCE four times yesterday to try to mitigate the thing. During the first installation, I ticked the choice to get the updates during the installation. When it rebooted, I came straight to the same problem. A wallpaper but no interface for login.

I installed again Ultimate Edition from scratch without network. Everything immediately ran fine. I did an image through clonezilla. Then I updated it again. Same problem.

I suspect something with lightdm which is among the updates. I have been through the config files in /etc/lightdm and in /usr/share/lightdm but I could not find any big differences before and after update.

I just noticed in Ubuntu 16.04, the 50-unity-greeter does not appear, replaced by a 60-lightdm-gtk-greeter. But in terms of content, they are almost equivalent.
I also noticed some remaining [SeatDefaults] among those files which should be replaced with [Seat:*]. The first one matches the old syntax and some comments appear in the lightdm logs about that.

Other things which may help:
- If I start it up through the "upstart" line in Grub, I get the CLI. I can type sudo lightdm start and it works fine. But a "classic" boot leads to the dead screen.
- When the computer is stucked on that black screen, a CTRL+ALT+F1/2/3/... does not allow to get a console. All I can see is the blinking cursor.
- When it is stuck, a CTRL+ALT+DEL works fine and launches a reset.

So any idea why the updates generate a loss of login screen?

Re: No more opening session screen

PostPosted: Sat Jul 30, 2016 9:46 am
by speedstream
OK!

Digging deeper, I found the problematic package.

Everything begins when I apply this update:
ultimate-edition-5.0-plymouth

Once updated, the Ultimate Edition 5.0 splash screen is changed to the black wallpaper I wrote about and the login screen never comes back.

I read plymouth is a process very close to hardware because it runs almost before everything. So he's a good "client" to my eyes.