Ubuntu 19.10 switching users broken

[Raphaël Godart]

I've performed an upgrade from Ubuntu 19.04 to 19.10 5 days ago by running the command "sudo do-release-upgrade". The upgrade went well, without errors. I've installed all updates to date (22 sept 2019). One thing seems broken since the upgrade to 19.10: it is not possible to switch users when using the Nouveau driver.

Prerequisites:

- Use Ubuntu 19.10
- You need at least 2 users (e.g. user1 and user2)
- The Nouveau drivers must be used

Step to reproduce:

- Start your computer
- At the graphical login prompt, log in with user1: user1 is able to log in, its desktop is shown
- While logged into the desktop of user1, choose "Switch user"
- When back at the user selection screen, choose the profile of user2
- Provide the password for user2 and attempt log in

RESULT: the desktop of user2 is never shown. Instead, the lock screen is shown. After pressing [Enter] to hide the lock screen, the login prompt for user1 is displayed. On that screen, it is possible to press "Log in as another user" and provide the password for user2 again. A login attempt results again in the lock screen being displayed. it is never possible to login in as user2.

NOTE 1: the same happens when user2 was the first to log in after a reboot of the system. User2 is able to log in, and user1 is then stuck in a login loop.

NOTE 2: this bug doesn't happen when the proprietary NVidia driver is used (the version which can be installed via the Software & updates screen, version 340.107).

[Daniel van Vugt (vanvugt)]

Please:

1. Run:

   apport-collect 1844944

   to send use more information about the machine.

2. Reproduce the switching failure and then immediately run:

   journalctl -b0 > journal.txt

   and attach the file 'journal.txt' here.

[Raphaël Godart (raphgodart)]

I've now performed apport-collect 1844944.

I also reproduced the user switch failure and generated journal.txt immediately after. Journal.txt is attached.

[Daniel van Vugt (vanvugt)]

I wonder if this bug really is Nouveau specific, or if it's just KMS-specific.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Confirmed with Intel graphics too.

[Raphaël Godart (raphgodart)]

Thanks for fixing this! Will Ubuntu 19.10 get Gnome 3.34.1?

[Sebastien Bacher (seb128)]

Yes, that update is available in the standard archive now

[Matthew Gordon (matthewgordon)]

I've been getting the exact same behaviour and I still have this problem (as of December 31) with 19.10 and everything up-to-date. I'm using the amdgpu drivers though.

[Daniel van Vugt (vanvugt)]

This bug is closed so if you continue to experience problems then please open a new bug by running:

  ubuntu-bug gdm3