lightdm: screen does not wake up on mouse/keyboard events

[Douglas Silva]

Description: When session is locked either using dm-tool or light-locker, lightdm greeter is functional (you can type your password and press Enter to unlock the session) but screen is not turned on, and remains turned off even when you move the mouse or press any key.

Although, it doesn't occur when you close your session instead locking it.

Additional info:
* xorg: 1:7.7+19ubuntu12
* lightdm 1.28.0-0ubuntu1
* xfce4-session: 4.12.1-6ubuntu1

From lsb_release:
Description: Ubuntu 19.04
Release: 19.04

* Reproducible on other distributions as well. See here: https://bugs.archlinux.org/task/59750
* Reproducible on both Intel UHD Graphics and AMDGPU Graphics.

Steps to reproduce:
* Lock the running session using lightdm
* Screen is turned off, but it won't turn back on when you move the mouse or use the keyboard
* You can type the password and press Enter to unlock the session. It the password is correct, the screen will finally turn on and you will be at your desktop.

Note: switching out and then switching back to tty7 restores visibility of the lock screen.

On Arch Linux, downgrading to xorg-server{,-common} 1.20.0-9 makes the screen behave as expected.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: xorg 1:7.7+19ubuntu12
ProcVersionSignature: Ubuntu 5.0.0-13.14-generic 5.0.6
Uname: Linux 5.0.0-13-generic x86_64
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
BootLog: Error: [Errno 13] Permissão negada: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: XFCE
Date: Mon Apr 22 02:06:42 2019
DistUpgraded: Fresh install
DistroCodename: disco
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Integrated Graphics Controller [8086:22b1] (rev 21) (prog-if 00 [VGA controller])
   Subsystem: Dell Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Integrated Graphics Controller [1028:0725]
InstallationDate: Installed on 2019-04-22 (0 days ago)
InstallationMedia: Xubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 1bcf:28c0 Sunplus Innovation Technology Inc.
 Bus 001 Device 002: ID 8087:07dc Intel Corp.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Dell Inc. Inspiron 11-3162
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.0.0-13-generic root=/dev/mapper/xubuntu--vg-root ro quiet splash vt.handoff=1
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/31/2018
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 2.4.0
dmi.board.name: 0NM68T
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: Not Specified
dmi.modalias: dmi:bvnDellInc.:bvr2.4.0:bd01/31/2018:svnDellInc.:pnInspiron11-3162:pvr2.4.0:rvnDellInc.:rn0NM68T:rvrA00:cvnDellInc.:ct8:cvrNotSpecified:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: Inspiron 11-3162
dmi.product.sku: 0725
dmi.product.version: 2.4.0
dmi.sys.vendor: Dell Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.97-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 19.0.2-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.4-1ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.0.1-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20180925-2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

[Launchpad Janitor (janitor)]

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

[He Xuxin (tomacat-deactivatedaccount)]

I have same the issue on Debian after I upgrade to Debian buster. In my experience, it looks like related to Linux kernel. This bug can't reproduce on Linux 4.9:

Linux tomacat 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux
Linux tomacat 4.9.0-9-amd64 #1 SMP Debian 4.9.168-1+deb9u3 (2019-06-16) x86_64 GNU/Linux

But I can reproduce on Linux 4.19:

Linux tomacat 4.19.0-6-amd64 #1 SMP Debian 4.19.67-2+deb10u1 (2019-09-20) x86_64 GNU/Linux
Linux tomacat 4.19.0-5-amd64 #1 SMP Debian 4.19.37-5+deb10u2 (2019-08-08) x86_64 GNU/Linux

May be I should report it to Debian bug tracking system.

[bryncoles (brunomatti)]

I think I have the same bug.

I use Xubuntu 19.10.

When the screen locks, mouse and keyboard events will lake me to the unlock screen. Password is accepted, but screen never shows the desktop. I can log out and log in again to restore the desktop, but of course this closes all applications.