Lock screen after idle time freezes unity

[Luiz Angelo Daros de Luca]

Hello,

I recently upgrade to 14.04. My system uses fglrx provided by 14.04.

When I lock manually the screen, I get no problem. I can even sleep the system without problem. However,
when the screen is locked by idle time, I cannot unlock it.

At this point, I can see the screen but with some kind of translucent panel over it. Mouse also works. I tried to type blink the password but I had no luck. I only get a working system by going text mode (ctrl+alt+f1) and restarting lightdm. No dmesg or Xorg logs seems to indicate any error. The only strange log was in .xsession-errors.old:

init: processos unity-settings-daemon main (2495) terminados com status 1
init: processos gnome-session (Unity) main (2539) terminados com status 1
init: processos unity-panel-service main (2572) terminados com status 1
init: processos hud main (2536) terminados com status 1
init: processo indicator-powermain (2740) morto pelo sinal TERM
init: processo indicator-datetimemain (2741) morto pelo sinal TERM
init: processo indicator-soundmain (2747) morto pelo sinal TERM
init: processo indicator-printersmain (2748) morto pelo sinal TERM
init: processo indicator-sessionmain (2768) morto pelo sinal TERM
init: processo indicator-syncmain (2795) morto pelo sinal TERM
init: processo update-notifier-crash (/var/crash/_usr_bin_istanbul.1000.crash)main (4987) morto pelo sinal TERM
init: processos unity-panel-service-lockscreen main (7447) terminados com status 1
init: Disconnected from notified D-Bus bus
init: processos at-spi2-registryd main (2538) terminados com status 1

But as it has no time info, I cannot tell when they happened.

At least another user faces the same problem:
http://ubuntuforums.org/showthread.php?t=2214421

And this seems to be different from bug 1283938 as pm sleep/wake works as expected.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.1.2+14.04.20140328.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-20.42-generic 3.13.7
Uname: Linux 3.13.0-20-generic x86_64
NonfreeKernelModules: fglrx
.tmp.unity.support.test.0:

ApportVersion: 2.14-0ubuntu1
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Wed Apr 2 00:01:05 2014
DistUpgraded: 2014-03-31 21:24:46,145 DEBUG enabling apt cron job
DistroCodename: trusty
DistroVariant: ubuntu
DkmsStatus:
 fglrx-updates, 13.350.1, 3.11.0-18-generic, x86_64: installed
 fglrx-updates, 13.350.1, 3.13.0-20-generic, x86_64: installed
 vboxhost, 4.3.10, 3.11.0-18-generic, x86_64: installed
 vboxhost, 4.3.10, 3.13.0-20-generic, x86_64: installed
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Turks XT [Radeon HD 6670/7670] [1002:6758] (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:0012]
InstallationDate: Installed on 2012-10-19 (529 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
JockeyStatus:
 kmod:wl - Broadcom STA wireless driver (Proprietário, Desativado, Não está em uso) [auto-install]
 kmod:fglrx - Video driver for the AMD graphics accelerators (Proprietário, Desativado, Não está em uso)
 kmod:fglrx_updates - ATI Fire GL (Proprietário, Habilitado, Não está em uso)
MachineType: Dell Inc. XPS 8300
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-20-generic root=UUID=6633d579-d782-47ec-ad5a-22abac1412a0 ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: Upgraded to trusty on 2014-04-01 (1 days ago)
dmi.bios.date: 10/17/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A06
dmi.board.name: 0Y2MRG
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 3
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA06:bd10/17/2011:svnDellInc.:pnXPS8300:pvr:rvnDellInc.:rn0Y2MRG:rvrA01:cvnDellInc.:ct3:cvr:
dmi.product.name: XPS 8300
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.11+14.04.20140328-0ubuntu1
version.fglrx-installer: fglrx-installer N/A
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.52-1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.0-4ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.0-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.15.0-1ubuntu7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
xserver.bootTime: Tue Apr 1 23:48:17 2014
xserver.configfile: default
xserver.errors:
 open /dev/dri/card0: No such file or directory
 AIGLX error: failed to open /usr/X11R6/lib64/modules/dri/fglrx_dri.so, error[/usr/X11R6/lib64/modules/dri/fglrx_dri.so: cannot open shared object file: No such file or directory]
 AIGLX error: failed to open /usr/lib64/dri/fglrx_dri.so, error[/usr/lib64/dri/fglrx_dri.so: cannot open shared object file: No such file or directory]
 AIGLX error: failed to open /usr/X11R6/lib/modules/dri/fglrx_dri.so, error[/usr/X11R6/lib/modules/dri/fglrx_dri.so: cannot open shared object file: No such file or directory]
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.15.0-1ubuntu7
xserver.video_driver: fglrx

[Launchpad Janitor (janitor)]

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

[Louis (louisdk)]

This problem does also affect me.

After upgrading Ubuntu 12.04 -> 14.04 I also experience freeze after waking up my laptop from suspend. The only way to login is to reboot the machine. Restarting lightdm doesn't help.

I use the nouveau-driver.

Hardware-specs: http://support.lenovo.com/en_DK/landing.page?qpq=6458-AT7

[Marco Trevisan (Treviño) (3v1n0)]

Can you still experience this after last updates?

[Mohammad Javad Naderi (mjnaderi)]

I updated Ubuntu 14.04, but this bug still exists...

[Marco Trevisan (Treviño) (3v1n0)]

Mh... This might be similar to bug #1315369?

Can you try to perform the debug actions I posted on that bug?

[Launchpad Janitor (janitor)]

[Expired for unity (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Unity because there has been no activity for 60 days.]

[bguiz (c-ubuntuone-h)]

Not sure if my problem is due to the same reasons, as the lock screen is completely frozen - cannot even `Ctrl+Alt+F1` to go to tty, and mouse will not move. Otherwise exactly the same: Screen when going to locking manually using `Ctrl+Alt+L`works fine and responds to mouse/ keyboard. Screen when locked from a timeout is completely unresponsive. The only thing that responds is `Alt+SysRq+REISUB`.

[bguiz (c-ubuntuone-h)]

I'll just add that I have posted some questions about this (with a more complete description) on askubuntu.com:

- http://askubuntu.com/q/503184/7593
- http://askubuntu.com/q/503238/7593

[John H. Embretsen (johnemb)]

I experience this issue as well. It happens with Ubuntu 14.04 when leaving the computer idle long enough for it to lock the screen due to idle timeout. It does not happen every time it goes idle, but every now and then. More often the past couple of months.

The only resolution that I know of is to do CTRL-ALT-F1, log in and do "sudo service lightdm restart", or to reset the computer, but such a resolution is fatal to all running applications and open documents.

I also see others experiencing the same issue, for example in http://ubuntuforums.org/showthread.php?t=2214421.

What other information is required in order to get this bug triaged?

[Bostjan Skufca Jese (bostjanskufcajese)]

I am also experiencing this one, it is annoying (if I put it mildly).

I have few other ubuntu installations (fresh ones, not upgrades from pre-14.04 versions) and they do not exhibit this behaviour.

Will compare filesystems tonight and report if I discover which difference is/was relevant.

b.

[John H. Embretsen (johnemb)]

Lately I seem to be hit by this issue every time the desktop idles out to the lock screen.
A workaround, that is not acceptable in the long run, seems to be to lock the screen manually every time I leave the computer, to prevent the idle timeout.

[psnizek (psnizek-i)]

Exactly the same issue here. Fresh installation and opensource (no catalyst) ati drivers (Radeon HD 4670). This is frustrating, especially as it is already half a year after the 14.04 release. When 12.04 came out, I changed the graphics card (removed NVidia 8800 and replaced it by Radeon 4670) on my workstation because I couldn't get the system work correctly. Do we have to change graphics cards possibly everytime after a major release?? Pardon me for this small rant, but this is utterly frustrating. That said, I'd like to mention that the broken "suspend" function hasn't been fixed now in years. We run more than 5 different computers and laptops here in the office. Not one is able to suspend and to resume correctly. I know that doesn't belong into this thread, but I just needed to rant and unload some frustration that I picked up over months and years. Other than that, I love Ubuntu :-) (despite some new window/menu related focusing issues in Unity lately...)

[John H. Embretsen (johnemb)]

Update: Previously mentioned "workaround" (comment #13) is not working. It probably worked a few times by accident. I have lately seen just as many freezes with manual locking as with timeout locking. I have started to disable and avoid screen locking as much as possible, but that is of course not a good security strategy.

My graphics card is Sapphire Radeon HD 6850, open source (default) drivers.

[Andreas E. (andreas-e)]

This started to happen for me occasionally after the upgrade to 14.10 (so it did not happen for me in 14.04).

Either the lockscreen does not yet appear (and it shows a frozen buffer of the last view of the desktop), or it shows the lockscreen, but doesn't respond to keyboard (password input) or mouse clicks. Closing the laptop lid does not go back to stand-by but keeps the frozen screen on. I have to do ctrl+alt+f1 and restart the session.

[Marco Trevisan (Treviño) (3v1n0)]

When this happens, can you move to tty1, attach to compiz process (sudo gdb `pidof compiz`) and do "bt full" on it?

You also need to have unity/compiz debug symbols installed¹

[1] https://wiki.ubuntu.com/DebuggingProgramCrash#Debug_Symbol_Packages

[david howell (c-divid-z)]

I am having same exact issue on brand-new install of 14.04 on homegrown computer. I am new to Linux... Just got tired of Windows when WIN8 was released. Learning about ctrl+alt+f1 will be helpful until a fix (?) Is released.

[Tin Tvrtkovic (tinchester)]

This has been happening to me intermittently (~10% of the time?).

I've installed the debug symbols for compiz-core and unity, will try to attach to compiz when it happens again.

Intel Haswll i5 GPU.

[Andreas E. (andreas-e)]

Can you give the exact compiz debug package? compiz-dbg does not exist, and following the wiki instructions can also not find the package:
sudo apt-get install compiz-dbgsym=1:0.9.12+14.10.20140918-0ubuntu1

This is a quite serious issue to me, is there no other way to close the lockscreen from tty without killing the session and all work?

[Andreas E. (andreas-e)]

I was able to install compiz-core-dbgsym=1:0.9.12+14.10.20140918-0ubuntu1 and have been trying to do
    sudo gdb `pidof compiz`
but it gives me (2380 is the pid of compiz):
    2380: File or directory not found
    (gdb) bt full
    No stack.

[chau (chau-nguyenviet)]

Hi,
I have the same problem. I installed the newest and updated Ubuntu 14 on my Vaio S series two days ago.
The screen lock worked fine for a couple of times , but it froze after auto locked out today.
After locked out, I can not see the password promt . Mouse still worked Alt-Ctrl-Del bring up the [Suspend|Reboot|Power off] panel but was blured and I could not click on them.

I had to switch to Console and do a lightdm restart.

Please fix this .

[Eric (eric-woodruff)]

In a shell I am able to export DISPLAY variable and unity --replace to work around the problem.

[tjw (tjw-tjw)]

I wonder if this may be related to bug 1313436.

It happens to me about 10% of the time. Sometimes the lock screen or desktop after logging in is just incredibly slow to draw, but it then recovers. I've also noticed that even though the screen isn't updating, login works properly and even though the screen is black, the mouse cursor is resonspive when hovering over where the different windows on my desktop should be drawing at the time.

I am able to run 'killall -HUP unity' to fix the issue which is probably the same thing as running 'unity --replace'.

[nqf52942 (nqf52942)]

hi there,

my Dell Vostro works fine with Ubuntu 14.04 LTS 64bit. the only thing is, when activate
the other video driver (default is X.Org-X-Server - AMD/ATI-Grafikdriver) the notebook hangs up after hibernation or standby.

when me use fglrx or fglrx-updates driver (for better performance), the notebook reproducible hangs up after hibernation or standby.

now me use the default open source driver. me only will report the error,when its an iusse from the closed source driver, and the community cant nothing do, delete my post.

respectfully, vostro 3550 user.
(i5-2450M CPU, AMD Radeon 6600M and 6700M Series, 8GB RAM)

[Andreas E. (andreas-e)]

This happens to me at least once every day, each time the whole session, open windows and unsaved documents lost (I save, yes, but the fact that at any time things can be lost makes this a critical issue for me). Is there a chance this can be fixed?

[Andrea Azzarone (azzar1)]

@Andres which version of unity are you running? Can you run
apt-cache policy unity

[Andrew Bolt (andrew-bolt+ubuntu)]

I'm seeing this too. Installed: 5.20.0-0ubuntu3 .
The machine wakes up with an unresponsive desktop. Xorg seems to be using 100% CPU, nothing else significant. Killing the compiz process allows the session to recover to the screensaver password unlock screen.

[João Cruz Jr (joaoacj-gmail)]

This is so annoying that make think, for the first time since 2005, to switch to another distro.

[Andreas E. (andreas-e)]

I have 7.3.1+14.10.20141016-0ubuntu1 (unity-proposed and unity-backports enabled).

Unfortunately I did not succeed just restarting unity (without restarting Xorg):
env DISPLAY=0,0 unity --restart
Gives error output (I don't have it kcomplete) with "unknown job unity-panel-service". If it can be worked-around, how could it be it done?

[tjw (tjw-tjw)]

I see I made a mistake in my above comment. It's 'killall -HUP compiz' that I've been using, not the unity process.

One recurring theme I've noticed is that it seems like every time this happens, the Software Updater icon is in my panel. There is no window for Software Updater and I can't make one visible.

I'm wondering if if this bug may be related to a button getting added to the panel while the password screen is up. I've set my computer to never check for updates now to see if that keeps this from happening.

[shadyyx (krajcar-peter-8)]

I also have this issue. At work I need to use too many tools so turning the laptop off at the end of each day and turning it on while starting all the applications and arranging them on the screens (I use 3) is a no go. Therefore I suspend the computer (simply by closing the laptop's lid). Very often after opening the lid and waking up the computer the login screen is frozen - either in a way that I can use my mouse but cannot gain focus after clicking into the login field (also just typing the password and confirming by Enter key does not work) or that the screens are split from one half of one monitor to the half of the screen on the other monitor.

To be able to use 3 monitors with Ubuntu 14.04 (one laptop's + 2 monitors) I had to upgrade the kernel and install the Intel graphic drivers.

Kernel version: 3.17.0-031700-generic
Intel drivers: *-display
       description: VGA compatible controller
       product: Haswell-ULT Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 0b
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:46 memory:f7800000-f7bfffff memory:e0000000-efffffff ioport:f000(size=64)

I used these resources to upgrade the kernel and install the Intel drivers: http://ubuntuhandbook.org/index.php/2014/10/install-upgrade-kernel-3-17-ubuntu/ and http://askubuntu.com/questions/141606/how-to-fix-the-system-is-running-in-low-graphics-mode-error

Though there is no problem with the setup I am not sure whether it may lead to problems with lightdm and freezing. I am still trying to keep the system up-to-date. Any ideas?

[pronoy chopra (pronoyc)]

I have this issue everytime. I think I am just going to get rid of Unity and install something like Cinnamon or some sort of window manager like Awesome.

[João Cruz Jr (joaoacj-gmail)]

Upgraded to 15.04 and the bug is not present anymore.

[snowch (snowch)]

Is there a workaround for this issue?

[Sebastien Bacher (seb128)]

That bug seems rather a video driver one than an unity issue. Could you try if that's still happening with most recent versions (some comments suggest it has been resolved)

[Launchpad Janitor (janitor)]

[Expired for Unity because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for unity (Ubuntu) because there has been no activity for 60 days.]

[Muhannad H. Shelleh (mhh1422)]

Still exists I think. I am facing this issue since last week.

I have noticed that it happens when I am using netbeans (maybe OpenJDK issue?), when the screen locks for idle, I can login but then I can not set focus to any window other than netbeans, and at the same time can not use netbeans.

However, I can change between applications using alt+tab, but without being able to use the switched-to application, except I can close it using alt+f4. When I close netbeans I get everything working well, and starting netbeans again resume the problem and this time I can not even alt+f4! I used to open a terminal (ctrl+alt+t) and kill netbeans process at this phase.

[Muhannad H. Shelleh (mhh1422)]

One more notice: when I closed netbeans, I found that left mouse click acts as a middle mouse click in chrome browser (opens links in new tab, closes tabs) and the middle one is not working!

[Pavel Lunin (plunin)]

Got very same issue after upgrading to Kubuntu 15.10 from 15.04. In my case it's nvidia.

[Rick Harris (rickfharris)]

Still a problem in Xenial 16.04. I'm using Intel gfx driver so based on others using different video drivers (ati, nouveau and now intel) may indicate the problem lies at least not with the video drivers.

Perhaps it's a problem with Unity's lockscreen?

[Hammeh (easily-remembered)]

I'm still getting this issue on Ubuntu 16.04. It is very annoying! When the screen goes to sleep, pressing any key will turn the laptop screen back on but neither the mouse or keyboard inputs appear to work on the login window. I can't press Ctrl+Alt+F1 either so my only option is a hard reset of the laptop.

uname -a
Linux sleekbook 4.4.0-22-generic #40-Ubuntu SMP Thu May 12 22:03:46 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

*-display
       description: VGA compatible controller
       product: Trinity [Radeon HD 7500G]
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 1
       bus info: pci@0000:00:01.0
       version: 00
       width: 32 bits
       clock: 33MHz
       capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
       configuration: driver=radeon latency=0
       resources: irq:30 memory:e0000000-efffffff ioport:3000(size=256) memory:f0300000-f033ffff

modinfo radeon
filename: /lib/modules/4.4.0-22-generic/kernel/drivers/gpu/drm/radeon/radeon.ko
license: GPL and additional rights
description: ATI Radeon
author: Gareth Hughes, Keith Whitwell, others.

[Marco Trevisan (Treviño) (3v1n0)]

Hammeh, can you connect via SSH to the machine or access from tty1 to it?

As if you can it would be nice if you could install the debug symbols for unity and compiz, and attach to the compiz process with gdb in order to get a backtrace.

See ubuntu wiki for more infos: https://wiki.ubuntu.com/Backtrace#Already_running_programs

[Hammeh (easily-remembered)]

Marco, in typical fashion I have tried all evening to recreate this with no success, after getting it consistently through reboots yesterday.

I wasn't able to drop to tty1 when it happened, but I will grab the backtrace via SSH the next time it happens.

[Jeremiah Peschka (peschkaj)]

This happens to me on an 16.04 installation as well (kernel 4.4.0-24-generic. Hardware is a pair of EVGA Titan X. I can switch to a terminal using Ctrl+Alt+1 and I grabbed the attached information from gdb over two separate runs.

The system hangup occurs every time I lock the screen and the monitors go idle. I don't see anything troubling in journalctl happening at the same time that I'm attempting to resume.

[Emmanuel C. (emmanuel-colin-r)]

Reading this thread there seems to be 2 distinct bugs.

I am getting the really bad one (frozen keyboard so no access to tty on the machine, only remote ssh and restart lightdm possible to get access again) on a HP 5750 AMD64 Athlon x2.

System hangup occurs when the screen locks after going idle for a while, or when switching between two logged on users.

This didn't happen with 14.04 i386, so for this hardware it's specific to 16.04 (both with i386 and i686).

I installed debug symbols for unity/compiz/lightdm.
Attaching with gdb on unity or compiz doesn't yield any stack.
Attaching to lightdm gives the same stack after and before system hangup (see attachment).

Any help greatly appreciated!

[Danilo (danilo-k)]

Same bug for me in a 16.04 brand new installation.

Asus mboard and Radeon video card

It happens randomly but always when the screen goes to sleep

No way to use keyboard or mouse ... just power off and on again

The same machine with the previous LTS version had no problem at all

Any help appreciated...

[zhxq (zhxq)]

Yesterday when I went to sleep, I left the computer in lock screen.

Usually, when I leave the computer in lock screen, the screen would close in a certain time.

However, yesterday night, I left the computer in lock screen; and when I woke up ten hours later, the screen was still on the lock screen, but not closed as normal.

I tried to move my mouse, but nothing happened. I also tried to smash the keyboard, but also no respond. The only way for me to deal with the problem is to restart.

Any help? Thanks!

[Jonas Gustavsson (jogco)]

Similar experience as Emmanuel C (comment #47):

I have been running 14.04 LTS i386 (in different flavours) on two (old) HP dx5150 each with AMD Athlon 64 and (IGP) ATI RS480. These are used for development and test. Worked like a charm.

For a new project, I installed 16.04.1 LTS i386 on one of them, and immediately started having problems with the screen saver not exiting on keyboard/mouse activity.

Now, I installed 14.04.5 LTS 64bit and the problem seems now to have been backported... :(

And as Emmanuel describes, no keyboard activity, like Ctrl-Alt-F1, works. The only things that works is a) restarting lightdm when the problem occurs (using ssh, if I remember to install it...) and b) setting the idle time for the screen saver to Never so that the problem does not occur.

I am quite amazed over the longevity of this bug.

[Francis Chin (chinf)]

I had the issue that Emmanuel describes, with a fresh install of 16.04.1 LTS 64-bit on a self-built machine with Athlon 64 X2 CPU and IGP ATI RS690 (X1200) and the open source radeon driver and kernels from 4.4.0-31 to -38.

As per Jonas's comment #50, cannot switch TTY, but as I've enabled REISUB I can Alt-SysRq-R then E before I can regain control, but then systemd keeps restarting the desktop. A more stable workaround was to set up ssh and ssh in from another box and restart lightdm. Setting the idle time for the screen saver to Never was only partially satisfactory as manually locking the screen would also trigger the screen fade-out and thus the bug. Interestingly, manually blanking the screen using "xset s activate" would blank the screen and not trigger the bug, so it doesn't appear to be a DPMS problem.

While sshing in from another box, at the point of triggering the bug there was no output to Xorg.0.log, nor syslog, nor kern.log. However, after some attempted keyboard & mouse activity on the affected system, Xorg.0.log did show an MIEQ overflow backtrace:

(EE) [mi] EQ overflowing. Additional events will be discarded until existing events are processed.
(EE)
(EE) Backtrace:
(EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x558ad06155ce]
(EE) 1: /usr/lib/xorg/Xorg (mieqEnqueue+0x253) [0x558ad05f7083]
(EE) 2: /usr/lib/xorg/Xorg (QueuePointerEvents+0x52) [0x558ad04cf662]
(EE) 3: /usr/lib/xorg/modules/input/evdev_drv.so (0x7f1b3560f000+0x61f3) [0x7f1b356151f3]
(EE) 4: /usr/lib/xorg/modules/input/evdev_drv.so (0x7f1b3560f000+0x6a5d) [0x7f1b35615a5d]
(EE) 5: /usr/lib/xorg/Xorg (0x558ad0463000+0x94228) [0x558ad04f7228]
(EE) 6: /usr/lib/xorg/Xorg (0x558ad0463000+0xb96f2) [0x558ad051c6f2]
(EE) 7: /lib/x86_64-linux-gnu/libc.so.6 (0x7f1b3f2e6000+0x354a0) [0x7f1b3f31b4a0]
(EE) 8: /lib/x86_64-linux-gnu/libc.so.6 (__read+0x2b) [0x7f1b3f3dc9cb]
(EE) 9: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmHandleEvent+0x37) [0x7f1b406cdde7]
(EE) 10: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7f1b3b3d4000+0x4f9ec) [0x7f1b3b4239ec]
(EE) 11: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7f1b3b3d4000+0x498e6) [0x7f1b3b41d8e6]
(EE) 12: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7f1b3b3d4000+0x499af) [0x7f1b3b41d9af]
(EE) 13: /usr/lib/xorg/Xorg (dixSaveScreens+0x29e) [0x558ad04e84de]
(EE) 14: /usr/lib/xorg/Xorg (mieqProcessInputEvents+0x1e6) [0x558ad05f7706]
(EE) 15: /usr/lib/xorg/Xorg (ProcessInputEvents+0x19) [0x558ad04f7479]
(EE) 16: /usr/lib/xorg/Xorg (0x558ad0463000+0x539df) [0x558ad04b69df]
(EE) 17: /usr/lib/xorg/Xorg (0x558ad0463000+0x57c33) [0x558ad04bac33]
(EE) 18: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f1b3f306830]
(EE) 19: /usr/lib/xorg/Xorg (_start+0x29) [0x558ad04a4f59]
(EE)
(EE) [mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack.
(EE) [mi] mieq is *NOT* the cause. It is a victim.

As this suggested a problem with the graphics stack, I tried the latest drivers from the Oibaf PPA, and so far I haven't been able to reproduce the bug. I don't know which component/version is responsible for the apparent fix.

[Ivan Wolf (ivan-a-wolf)]

Here is the same problem in Ubuntu 16.04. By blocking the session, the screen goes black. By accessing the tty1 and end the process of compiz, you can log in again.
*-display
        Description: VGA compatible controller
        Product: Sky Lake Integrated Graphics
        Manufacturer: Intel Corporation
        Physical ID: 2
        Bus information: pci @ 0000: 00: 02.0
        Version: 06
        width: 64 bits

cat /usr/share/X11/xorg.conf.d/20-intel.conf
Section "Device"
    Identifier "Intel Graphics"
    Option "DRI" "3"
EndSection

[Hammeh (easily-remembered)]

This bug continues to exist in 16.10. Just had a freeze, was unable to interact with the system in any way (could not drop to tty1) - requires hard reset on my system.

[Roman (sapp)]

Same issue in 16.04.1 LTS, the laptop is Asus Zenbook UX32VD. Black screen, cursor moving.

To avoid restarting and losing all unsaved data, I did the following:
1. Switch to TTY1 (Ctrl+Alt+F1)
2. Log in
3. Kill compiz process:
sudo kill -9 `pidof compiz`
4. Switch back to TTY7 (Ctrl+Alt+F7)

All the graphics reappeared, didn't have to restart.

From what I understand, there is no solid solution here and it's probably related to video drivers. I switched to proprietary nvidia drivers yesterday, probably it was the reason. Or maybe it was related to the leftovers from Xfce which I also installed yesterday and then removed (and it didn't seem to go away that easily).

[K Marshall (kmar220)]

I am experiencing the issue where my console becomes completely unresponsive when the unity screensaver is activated.

I have tested some potential work arounds for console lockup when the unity screensaver activates under 16.04 (choose one) :
     Upgrade to 16.10
     Upgrade to 16.04.2
     Install the 16.04 HWE kernel and X packages
     Set Radeon option "EnablePageFlip" to "false"
     Set Radeon option "Accel" to "false"

Ubuntu 16.04 (64 bit) ; Unity desktop environment ; "radeon" driver ; Radeon X600 video card ; Dell Optiplex 745
VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV370 [Radeon X600/X600 SE] ( 1002:5b62 Subsystem: 1002:0b02 )

When the Unity screensaver activates, the screen fades to black and the monitor powers off. After that, the keyboard is unresponsive (not even num lock or scroll lock trigger their keyboard lights) and will not wake the system. The mouse is unresponsive and will not wake the system. Moving the mouse or pressing a number of keys will trigger an "[mi] EQ overflowing" error message and backtrace in /var/log/Xorg.0.log :

...
[ 408.605] (II) RADEON(0): Modeline "1152x864"x0.0 108.00 1152 1216 1344 160
0 864 865 868 900 +hsync +vsync (67.5 kHz e)
(EE) [mi] EQ overflowing. Additional events will be discarded until existing events are processed.
(EE)
(EE) Backtrace:
(EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x55f7683dbade]
(EE) 1: /usr/lib/xorg/Xorg (mieqEnqueue+0x253) [0x55f7683bd583]
(EE) 2: /usr/lib/xorg/Xorg (QueuePointerEvents+0x52) [0x55f768295862]
(EE) 3: /usr/lib/xorg/modules/input/evdev_drv.so (0x7fbf704d9000+0x61f3) [0x7fbf704df1f3]
(EE) 4: /usr/lib/xorg/modules/input/evdev_drv.so (0x7fbf704d9000+0x6a5d) [0x7fbf704dfa5d]
(EE) 5: /usr/lib/xorg/Xorg (0x55f768229000+0x94538) [0x55f7682bd538]
(EE) 6: /usr/lib/xorg/Xorg (0x55f768229000+0xb9922) [0x55f7682e2922]
(EE) 7: /lib/x86_64-linux-gnu/libc.so.6 (0x7fbf7a1b1000+0x354b0) [0x7fbf7a1e64b0]
(EE) 8: /lib/x86_64-linux-gnu/libc.so.6 (__read+0x2b) [0x7fbf7a2a769b]
 (EE) 9: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmHandleEvent+0x37) [0x7fbf7b598de7]
(EE) 10: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7fbf7629f000+0x4f9ec) [0x7fbf762ee9ec]
(EE) 11: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7fbf7629f000+0x498e6) [0x7fbf762e88e6]
(EE) 12: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7fbf7629f000+0x499af) [0x7fbf762e89af]
(EE) 13: /usr/lib/xorg/Xorg (dixSaveScreens+0x29e) [0x55f7682ae6ee]
(EE) 14: /usr/lib/xorg/Xorg (mieqProcessInputEvents+0x1e6) [0x55f7683bdc06]
(EE) 15: /usr/lib/xorg/Xorg (ProcessInputEvents+0x19) [0x55f7682bd789]
(EE) 16: /usr/lib/xorg/Xorg (0x55f768229000+0x53b7f) [0x55f76827cb7f]
(EE) 17: /usr/lib/xorg/Xorg (0x55f768229000+0x57dd3) [0x55f768280dd3]
(EE) 18: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7fbf7a1d1830]
(EE) 19: /usr/lib/xorg/Xorg (_start+0x29) [0x55f76826b049]
(EE)
(EE) [mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack.
(EE) [mi] mieq is *NOT* the cause. It is a victim.
(EE) [mi] EQ overflow continuing. 100 events have been dropped.

The only way to restore console operation was to completely kill the existing X11 session ...