I don't actually know if it's an xorg issue, but since upgrading to 15.10 I've been experiencing a lot of random lockups. Nothing responds, can't restart X11 with ctrl-alt-backspace (I have that enabled) or switch to a terminal using ctrl-alt-f1 or etc. I end up having to reboot by holding the power button.
I tried to send a bug report using apport-bug, so I hope the proper information is attached. Happy to help debug further, I haven't been able to find anything suspicious in /var/log/syslog so I don't know what to do further.
ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xorg 1:7.7+7ubuntu4
ProcVersionSignature: Ubuntu 4.2.0-18.22-generic 4.2.3
Uname: Linux 4.2.0-18-generic x86_64
.tmp.unity.support.test.0:
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: Awesome GNOME
Date: Thu Nov 26 12:26:03 2015
DistUpgraded: 2015-10-29 13:46:10,504 DEBUG enabling apt cron job
DistroCodename: wily
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GpuHangFrequency: Several times a week
GpuHangReproducibility: Seems to happen randomly
GpuHangStarted: Immediately after installing this version of Ubuntu
GraphicsCard:
Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b) (prog-if 00 [VGA controller])
Subsystem: Lenovo Device [17aa:220c]
InstallationDate: Installed on 2013-11-24 (732 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MachineType: LENOVO 20AQCTO1WW
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-18-generic.efi.signed root=UUID=db348109-4f22-485b-a9ad-5526ee0ff06e ro quiet splash acpi_backlight=vendor nomdmonddf nomdmonisw vt.handoff=7
SourcePackage: xorg
Symptom: display
Title: Xorg freeze
UpgradeStatus: Upgraded to wily on 2015-10-29 (27 days ago)
dmi.bios.date: 10/20/2014
dmi.bios.vendor: LENOVO
dmi.bios.version: GJET80WW (2.30 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20AQCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: 0B98405 STD
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrGJET80WW(2.30):bd10/20/2014:svnLENOVO:pn20AQCTO1WW:pvrThinkPadT440s:rvnLENOVO:rn20AQCTO1WW:rvr0B98405STD:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 20AQCTO1WW
dmi.product.version: ThinkPad T440s
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.12.2+15.10.20151015-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.64-1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.0.2-1ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.0.2-1ubuntu4
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+git20150808-0ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu3
xserver.bootTime: Thu Nov 26 12:25:06 2015
xserver.configfile: default
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
product id 4669
vendor AUO
xserver.version: 2:1.17.2-1ubuntu9
Status changed to 'Confirmed' because the bug affects multiple users.