Xorg server crashes with radeonsi drivers during surfing

[theghost]

Xorg crashes for a few seconds and screen turns black during normal desktop activity, running on Radeonsi drivers.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: xorg 1:7.7+7ubuntu2
ProcVersionSignature: Ubuntu 3.16.0-23.30-generic 3.16.4
Uname: Linux 3.16.0-23-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.14.7-0ubuntu7
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: Sun Oct 19 20:07:40 2014
DistUpgraded: Fresh install
DistroCodename: utopic
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Curacao XT [Radeon R9 270X] [1002:6810] (prog-if 00 [VGA controller])
   Subsystem: PC Partner Limited / Sapphire Technology Device [174b:e271]
InstallationDate: Installed on 2014-10-18 (1 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Alpha amd64 (20141016)
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcEnviron:
 LANGUAGE=de_DE
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.16.0-23-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/02/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.90
dmi.board.name: H81M-HDS
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.90:bd07/02/2014:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnH81M-HDS:rvr:cvnToBeFilledByO.E.M.: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: To Be Filled By O.E.M.
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: Sun Oct 19 19:27:53 2014
xserver.configfile: default
xserver.devices:
 input Power Button KEYBOARD, id 6
 input Power Button KEYBOARD, id 7
 input HID 046a:0021 KEYBOARD, id 8
 input HID 046a:0021 KEYBOARD, id 9
 input Microsoft Microsoft® Comfort Mouse 4500 KEYBOARD, id 10
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.16.0-1ubuntu1
xserver.video_driver: radeon

[penalvch (penalvch)]

Mathias Dietrich, thank you for reporting this bug to Ubuntu. Utopic reached EOL on July 23, 2015.
See this document for currently supported Ubuntu releases: https://wiki.ubuntu.com/Releases

If this is reproducible on a supported release, please file a new report.