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[Launchpad Bug Tracker <1865323@xxxxxxxxxxxxxxxxxx>]

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

** Changed in: lightdm-gtk-greeter (Ubuntu)
       Status: New => Confirmed

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https://bugs.launchpad.net/bugs/1865323

Title:
  Switch User+DPMS then click Unlock causes a delay with black screen

Status in lightdm-gtk-greeter package in Ubuntu:
  Confirmed

Bug description:
  ed@userver:~$ lsb_release -rd
  Description:	Ubuntu Focal Fossa (development branch)
  Release:	20.04
  ed@userver:~$ apt-cache policy pkgname lightdm-gtk-greeter
  lightdm-gtk-greeter:
    Installed: 2.0.6-0ubuntu1
    Candidate: 2.0.6-0ubuntu1
    Version table:
   *** 2.0.6-0ubuntu1 500
          500 http://us.archive.ubuntu.com/ubuntu focal/universe amd64 Packages
          100 /var/lib/dpkg/status
  N: Unable to locate package pkgname

  I'm not sure if the issue is in the LightDM greeter, but it only
  happens after I use the greeter.

  I expect my desktop to get displayed soon after I click "Unlock" on
  the greeter.

  What happens is that there is a delay with black screen of at least 2
  seconds (often 10 minutes).

       Details:

  When I "Switch User" and then click unlock button, I get a black
  screen with no mouse cursor for 2 seconds, and then black screen with
  mouse cursor for approx 0.65 seconds for every minute my PC was in
  DPMS (after 495 minutes in DPMS the black screen is up for a very long
  321 seconds).  If I'm on greeter screen and keep moving mouse to avoid
  DPMS, then I only have the 2 second delay.

  This only happens with NVidia drivers (nouveau drivers don't have any
  delay at all). I tested on fresh installs of both Ubuntu 19.10 with
  default gdm and UbuntuStudio 19.10 with LightDM and now UbuntuStudio
  20.04 nightly build. If I prevent DPMS by moving my mouse every few
  minutes, then I only have the 2 second delay. I am not able to
  reproduce this issue on UbuntuStudio 18.04.

  Methods that cause delay:
  - Click "Switch User" on the Whisker menu. 
  - Click "Switch User" on the "Action Buttons" on panel 0. 
  - dm-tool switch-to-greeter   (displays greeter)
  - dm-tool lock                (starts DPMS, then greeter)

  Methods that DO NOT cause delay:
  - Click "Lock" on the Whisker menu. 
  - Click "Lock" on the "Action Buttons" on panel 0. 
  - xdotool key Ctrl+alt+l      (runs screensaver, only delay if click "Switch User")
  - xflock4                     (runs screensaver, only delay if click "Switch User")
  - xset dpms force off         (runs screensaver, only delay if click "Switch User")

  Another interesting symptom is that the first 2 second black screen
  does have the mouse pointer in 19.10, but not in 20.04.  Also, If I
  Lock instead of Switch User, then my desktop comes up immediately.

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: lightdm-gtk-greeter 2.0.6-0ubuntu1
  ProcVersionSignature: Ubuntu 5.4.0-14.17-lowlatency 5.4.18
  Uname: Linux 5.4.0-14-lowlatency x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.20.11-0ubuntu18
  Architecture: amd64
  Date: Sun Mar  1 00:56:12 2020
  InstallationDate: Installed on 2020-02-29 (0 days ago)
  InstallationMedia: Ubuntu-Studio 20.04 LTS "Focal Fossa" - Alpha amd64 (20200227)
  ProcEnviron:
   LANGUAGE=en_US
   TERM=xterm-256color
   PATH=(custom, no user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: lightdm-gtk-greeter
  UpgradeStatus: No upgrade log present (probably fresh install)

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