Can't login after lock screen (black screen)

[brunolabs]

After locking screen and as a result the monitor going into sleep mode, I can't get the login screen anymore, the monitor stays in sleep mode forever.

In previous Ubuntu versions after pressing any key or the mouse, the login screen showed up, but not anymore. I have to restart the computer.

WORKAROUND: Swtiched from Unity to Ubuntu GNOME.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-34.53-generic 4.4.15
Uname: Linux 4.4.0-34-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Fri Aug 26 23:19:23 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RV410 [Radeon X700] [1002:5e4f] (prog-if 00 [VGA controller])
   Subsystem: Gigabyte Technology Co., Ltd RV410 [Radeon X700] [1458:2120]
   Subsystem: Gigabyte Technology Co., Ltd Device [1458:2121]
InstallationDate: Installed on 2016-07-12 (45 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
Lsusb:
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 002 Device 002: ID 045e:0734 Microsoft Corp. Wireless Optical Desktop 700
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: FUJITSU SIEMENS P5SD1-FM2
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-34-generic root=UUID=b2c81b2b-163d-41b4-869a-67882349ae49 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/03/2006
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0304
dmi.board.name: P5SD1-FM2
dmi.board.vendor: FUJITSU SIEMENS
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0304:bd01/03/2006:svnFUJITSUSIEMENS:pnP5SD1-FM2:pvrSystemVersion:rvnFUJITSUSIEMENS:rnP5SD1-FM2:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: P5SD1-FM2
dmi.product.version: System Version
dmi.sys.vendor: FUJITSU SIEMENS
version.compiz: compiz 1:0.9.12.2+16.04.20160801.3-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.2
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.1
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Fri Aug 26 23:12:08 2016
xserver.configfile: default
xserver.devices:
 input Power Button KEYBOARD, id 6
 input Power Button KEYBOARD, id 7
 input Liteon Microsoft® Wireless Receiver 700 v2.0 KEYBOARD, id 8
 input Liteon Microsoft® Wireless Receiver 700 v2.0 KEYBOARD, id 9
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.3
xserver.video_driver: radeon

[brunolabs (brunolabs)]

More details at:
https://ubuntuforums.org/showthread.php?t=2331684

[penalvch (penalvch)]

brunolabs, thank you for reporting this and helping make Ubuntu better.

Could you please provide the full computer model as noted on the sticker of the computer itself (not from the Bug Description)?

[brunolabs (brunolabs)]

Fujitsu Siemens Scaleo P
MB: Asus P5SD2
CPU: Pentium 4 3.2 GHz
RAM: 2 GB

[penalvch (penalvch)]

brunolabs, to clarify, what was the most recent previous version of Ubuntu where this issue didn't occur?

[brunolabs (brunolabs)]

In the previous LTS version (14.04) this issue didn't occur.
I switched to Ubuntu GNOME because of this issue, the unlock screen works correctly now. I hope this gives you more information for diagnosing the problem.

[penalvch (penalvch)]

brunolabs, to clarify, you switched to Ubuntu GNOME in 16.04 where it works?

[brunolabs (brunolabs)]

Correct.

[Jonathan Haws (hawsjr)]

I have the same issue on Xubuntu 16.04.1. A workaround for me is to hit Ctrl-Alt-F1 to bring up a tty, login, and run 'sudo service lightdm restart'.

This kills my session, which is annoying, but is faster than a reboot.

[phoenix (shamilek)]

I have same on XUbuntu with AMD Radeon 270X with proprietary drivers

[Himadri Mishra (hmishra2250)]

Have the same lock screen problem, along with the same hang appears on suspend. In my case it doesn't always hang, but does so occasionally.
Ubuntu GNOME 16.04 laptop HP-au008tx, kernel 4.7.10-040710

[Launchpad Janitor (janitor)]

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

[boris (borissjroetskov)]

I have the same issue on a Lenovo Thinkpad 13:

After the screen turns off, i'm unable to resume it (ctrl-alt-f1/f7 do nothing).

However: if i close the lid (thus putting the laptop into sleep mode) and reopen it, i'm able to resume my session.

Thinkpad 13
Core i7 6500
HD graphics 520

[Malcolm Meyer (malcolmtmeyer)]

Same issue, though it only seems to happen after the screen has been locked for some time, not immediately. I am running Ubuntu 16.10 64bit using the Gallium 0.4 graphics NV42, budgie desktop (was even worse with stock unity desktop) with NVIDIA graphics card. I just ssh in and restart my computer, but this is not ideal.

[Ivan Antonijevic (iantonijevic)]

Same issue, ubuntu 16.10 64bit, Lenovo ideapad Y700

[Aakash Nain (aknain)]

Same issue, ubuntu 16.04 64 bit, ASUS X541UV

[Kai-Heng Feng (kaihengfeng)]

Maybe use an SSH connection to see if computer is actually alive?

[uciel (ucielp)]

Same issue, 16.04.2-Ubuntu. Kernel 4.10.0-27-generic. HP Intel(R) Xeon(R) CPU E5620 @ 2.40GHz

[efficks (efficks)]

Same issue with Ubuntu 16.04.2 LTS HP Z620

[brunolabs (brunolabs)]

Also happens in Ubuntu 17.04.

[Jay Sevison (jsevison)]

same issue, 16.04.2-Ubuntu

Running a Dell Precision M4800

I was able to ssh to the machine without a problem.

[Mike Gioia (mikegioia)]

Same for me: Ubuntu 16.04, Intel i7, Gallium 0.4 on NVE6 graphics driver. I'm not using any custom graphics drivers, just Nouveau.

[Phelype (phe-h-o1)]

Same issue here.

Ubuntu 16.04.2 64-bit, Intel i7-4960X, Gallium 0.4 on NVE7 graphics driver.

Although it is a little different. The mouse cursor shows on screen normally. If I use Ctrl+Alt+F(1-6) I can access the terminal windows, but Ctrl+Alt+F7 makes the screen blank again and only the cursor appears.

Also this problem started a few days ago, but I have the same OS since 6 months ago.
The issue started when I was accessing my computer using Teamviewer 12.0.76279. It started specifically when I had to repeatedly log on and off (the teamviewer connection) to switch between user accounts (I have 2 in my computer). I don't know if this is somehow created the problem or it was just coincidence.

[sneha (sneha-ved7)]

Same issue here.
Do we have a solution?

[Benjamin Fischer (benfischer)]

What worked for me: install XScreenSaver (via `sudo apt install xscreensaver`), then reboot.

Thanks for this workaround from https://askubuntu.com/questions/620709/blank-screen-after-locking-screen (which has more possible workarounds).

My environment: Ubuntu 16.04.3 LTS with Xfce 4.12 on a Dell XPS 15 9560.