I'll attach kernel oops information after I've reboot the laptop.
The bug is not reprodicible at will, but happens regularly, usually after 1 day, but this time I've reached an uptime of 5+ days.
X11 freezes, the mouse pointer is updated but that's it, no updates to windows happen, nor have I've been able to detect any other effect from X11 events.
chvt 1 takes very long and results in a kernel oops.
chvt 7 sometimes restores the X11 session.
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.16.0-41-generic 3.16.0-41.57~14.04.1
ProcVersionSignature: Ubuntu 3.16.0-41.57~14.04.1-generic 3.16.7-ckt11
Uname: Linux 3.16.0-41-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.11
Architecture: amd64
Date: Thu Jul 2 21:38:28 2015
InstallationDate: Installed on 2015-05-15 (47 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
ProcEnviron:
LANGUAGE=de_AT:de
TERM=screen
PATH=(custom, no user)
LANG=de_AT.UTF-8
SHELL=/bin/bash
SourcePackage: linux-lts-utopic
UpgradeStatus: No upgrade log present (probably fresh install)
---
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC2: andreas 2011 F.... pulseaudio
/dev/snd/controlC1: andreas 2011 F.... pulseaudio
/dev/snd/controlC0: andreas 2011 F.... pulseaudio
CurrentDesktop: Unity
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=UUID=0398951e-5cc7-4364-a318-d133f94c2f92
InstallationDate: Installed on 2015-05-15 (219 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
MachineType: Notebook W230SS
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.16.0-55-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.16.0-55.74~14.04.1-generic 3.16.7-ckt19
RelatedPackageVersions:
linux-restricted-modules-3.16.0-55-generic N/A
linux-backports-modules-3.16.0-55-generic N/A
linux-firmware 1.134~gd~t
Tags: trusty
Uname: Linux 3.16.0-55-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm audio cdrom dip docker lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 04/15/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 4.6.5
dmi.board.asset.tag: Tag 12345
dmi.board.name: W230SS
dmi.board.vendor: Notebook
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: Notebook
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd04/15/2014:svnNotebook:pnW230SS:pvrNotApplicable:rvnNotebook:rnW230SS:rvrNotApplicable:cvnNotebook:ct9:cvrN/A:
dmi.product.name: W230SS
dmi.product.version: Not Applicable
dmi.sys.vendor: Notebook
One other thing, I need to reboot 3 times before X11 is completely restored:
1.) drops back to GRUB without interaction
2.) does not manage to activate graphics mode, so asks me for my passphrase in textmode, reboots a little bit later
3.) reboots to Ubuntu Unity.