Xorg crashed with SIGABRT in OsAbort()

[Kiwited]

Dual monitor setup. Screen colours are wrong on refresh from suspend (particularly Thunderbird) but all text blurry and shadowed with colour. At start from cold boot main screen has only a narrow strip on one side. Needs access to Gnome-control-center to adjust relationship of primary and secondary screens. Only a small movement of either screen brings up full screen on primary and the question "keep these settings". Answer yes and the problem has gone until the next cold boot.
The odd colouration of the monitors has happened since I upgraded to 15.10 so I expect to find a bug or two, however the narrow strip on the primary monitor has been an irritation with 15.04 as well.

$ lsb_release -rd
Description: Ubuntu Wily Werewolf (development branch)
Release: 15.10

ProblemType: Crash
DistroRelease: Ubuntu 15.10
Package: xserver-xorg-core 2:1.17.2-1ubuntu9
ProcVersionSignature: Ubuntu 4.2.0-14.16-generic 4.2.2
Uname: Linux 4.2.0-14-generic x86_64
ApportVersion: 2.19.1-0ubuntu2
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CrashCounter: 1
CurrentDesktop: GNOME
Date: Sat Oct 10 04:57:39 2015
DistUpgraded: 2015-10-08 09:54:28,697 DEBUG enabling apt cron job
DistroCodename: wily
DistroVariant: ubuntu
ExecutablePath: /usr/bin/Xorg
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RV710 [Radeon HD 4350/4550] [1002:954f] (prog-if 00 [VGA controller])
   Subsystem: PC Partner Limited / Sapphire Technology Device [174b:e990]
 Advanced Micro Devices, Inc. [AMD/ATI] Turks GL [FirePro V3900] [1002:674a] (prog-if 00 [VGA controller])
   Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Device [1002:0106]
MachineType: To be filled by O.E.M. To be filled by O.E.M.
ProcCmdline: /usr/bin/X vt7 -displayfd 3 -auth /run/user/116/gdm/Xauthority -nolisten tcp -background none -noreset -keeptty -verbose 3
ProcEnviron:
 SHELL=/bin/false
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_NZ.UTF-8
 LANGUAGE=en_NZ:en
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-14-generic root=UUID=67d7596a-e31e-42dc-b95a-28d68582477b ro quiet splash vt.handoff=7
Signal: 6
SourcePackage: xorg-server
StacktraceTop:
 OsAbort ()
 FatalError ()
 ?? ()
 xf86CloseConsole ()
 ddxGiveUp ()
Title: Xorg crashed with SIGABRT in OsAbort()
UpgradeStatus: Upgraded to wily on 2015-10-07 (1 days ago)
UserGroups:

dmi.bios.date: 04/07/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2501
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: M5A97 R2.0
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev 1.xx
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.:bvr2501:bd04/07/2014:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnM5A97R2.0:rvrRev1.xx: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 N/A
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.64-1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.0.2-1ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.0.2-1ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.17.2-1ubuntu9
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.2-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.0+git20150819-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20150808-0ubuntu3
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu3
xserver.bootTime: Sat Oct 10 05:15:20 2015
xserver.configfile: default
xserver.devices:
 input Power Button KEYBOARD, id 6
 input Power Button KEYBOARD, id 7
 input Logitech USB Optical Mouse MOUSE, id 8
 input Eee PC WMI hotkeys KEYBOARD, id 9
 input AT Translated Set 2 keyboard KEYBOARD, id 10
xserver.errors: RADEON(G0): [XvMC] Failed to initialize extension.
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.17.2-1ubuntu9
xserver.video_driver: radeon

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1237904, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.