Keyboard shortcuts unresponsive for several seconds

[Hadrien]

Sometimes global keyboard shortcuts like volume keys on multimedia keyboard or Ctrl+Alt+T to open a new terminal, do not respond immediately. They are buffered and respond after 15 seconds.

Started after I upgraded to 14.10
Occurs with Unity and Gnome Compiz.
Does not occur with normal Gnome and Xfce.

I can reproduce it with Kaffeine: just after I switch channel, all shortcuts are unresponsive for 15 seconds.

I can sometimes reproduce it with Firefox: I play a HTML 5 video and open a new tab or switch tab. Again all shortcuts are unresponsive for 15 seconds.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: compiz 1:0.9.12+14.10.20140918-0ubuntu1
ProcVersionSignature: Ubuntu 3.16.0-24.32-generic 3.16.4
Uname: Linux 3.16.0-24-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.14.7-0ubuntu8
Architecture: amd64
BootLog:
 * Setting sensors limits 
[ OK ]
  * Setting up X socket directories... 
[ OK ]
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: Tue Nov 11 20:30:48 2014
DistUpgraded: 2014-10-25 23:24:52,421 DEBUG enabling apt cron job
DistroCodename: utopic
DistroVariant: ubuntu
EcryptfsInUse: Yes
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RV770 [Radeon HD 4870] [1002:9440] (prog-if 00 [VGA controller])
   Subsystem: PC Partner Limited / Sapphire Technology Device [174b:114a]
InstallationDate: Installed on 2013-10-20 (387 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MachineType: Gigabyte Technology Co., Ltd. P55-UD3
PackageArchitecture: all
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-24-generic root=UUID=6ed824e6-8d9c-4383-913b-ca2bd564bfcb ro quiet splash vt.handoff=7
SourcePackage: compiz
UpgradeStatus: Upgraded to utopic on 2014-10-25 (16 days ago)
dmi.bios.date: 06/23/2010
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: F9
dmi.board.name: P55-UD3
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF9:bd06/23/2010:svnGigabyteTechnologyCo.,Ltd.:pnP55-UD3:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnP55-UD3:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
dmi.product.name: P55-UD3
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
version.compiz: compiz 1:0.9.12+14.10.20140918-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.56-1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.3.0-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.3.0-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.16.0-1ubuntu1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.0-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.4.0-2ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.914-1~exp1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu2
xserver.bootTime: Tue Nov 11 09:35:36 2014
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.16.0-1ubuntu1
xserver.video_driver: radeon

[Launchpad Janitor (janitor)]

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

[Dimitrios Piliouras (jimpil1985)]

I am seeing almost the exact same bug. Evey time i close a program (i.e. Firefox) i cannot use any global keyboard shortcuts (i.e alt+tab, ctrl+alt+t, ctrl+alt+arrows etc). I cannot even press the power button on my laptop...nothing happens and no buffering...it's like I 've never pressed anything...

[Hadrien (psydk)]

I have it sometimes when starting VLC by double-clicking on a video. I have to wait for about 20 seconds before VLC starts playing (though VLC process is actually started).

It looks like a lock exists somewhere but I wonder where. I am also having a hard time finding information about how to safely debug Compiz (without damaging my current Ubuntu installation). I already tried resetting all Compiz settings but it did not fix the issue.

I will try debugging VLC and break the process when the freeze occurs, hopefully the callstack will give me a clue.

[Hadrien (psydk)]

I upgraded to 15.04 and cannot reproduce the problem.

[Lysenko Denis (pharmasolin)]

Thank you for taking the time to report this bug. We have tried to recreate this on the latest release of Ubuntu and cannot reproduce it. This bug is being marked as Invalid. If you believe the problem to still exist in the latest version of Ubuntu please comment on why that is the case and change the bug status to NEW.