This is a similar issue as bug 1227569, but I'm filing a separate bug since I'm experiencing this on an ATI radeon card.
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xorg 1:7.7+1ubuntu8.1
ProcVersionSignature: Ubuntu 3.16.0-41.57~14.04.1-generic 3.16.7-ckt11
Uname: Linux 3.16.0-41-generic x86_64
.tmp.unity.support.test.0:
ApportVersion: 2.14.1-0ubuntu3.11
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: Wed Jul 1 11:20:33 2015
DistUpgraded: Fresh install
DistroCodename: trusty
DistroVariant: ubuntu
DkmsStatus:
vboxhost, 4.3.28, 3.16.0-37-generic, x86_64: installed
vboxhost, 4.3.28, 3.16.0-38-generic, x86_64: installed
vboxhost, 4.3.28, 3.16.0-39-generic, x86_64: installed
vboxhost, 4.3.28, 3.16.0-40-generic, x86_64: installed
vboxhost, 4.3.28, 3.16.0-41-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
Advanced Micro Devices, Inc. [AMD/ATI] Oland PRO [Radeon R7 240] [1002:6613] (prog-if 00 [VGA controller])
Subsystem: ASUSTeK Computer Inc. Device [1043:048b]
InstallationDate: Installed on 2015-05-16 (45 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
MachineType: Gigabyte Technology Co., Ltd. To be filled by O.E.M.
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-41-generic root=UUID=5f77a868-de36-4b0b-91e9-bd05e1f93bf8 ro quiet splash iommu=soft radeon.hard_reset=1 radeon.gartsize=2048 vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/29/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F2j
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: 970A-DS3P
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF2j:bd12/29/2014:svnGigabyteTechnologyCo.,Ltd.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnGigabyteTechnologyCo.,Ltd.:rn970A-DS3P:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
version.compiz: compiz 1:0.9.11.3+14.04.20150313-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.60-2~ubuntu14.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri N/A
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Wed Jul 1 10:26:57 2015
xserver.configfile: default
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.16.0-1ubuntu1.2~trusty2
xserver.video_driver: radeon
Alberto Mardegan, thank you for reporting this and helping make Ubuntu better. To see if this is already addressed, could you please test http://