The work-around I mentioned above (booting recovery + continue) does not seem to work reliably. It just took me half an hour to have a successful boot, to provide the apport-collect. A few more observations:
- For some reason my xorg.conf had been renamed to xorg.conf.11142015, without any xorg.conf in place. Apparently this must have happened yesterday, when my previous work around stopped working. I had the successful boot after renaming it back, but right now I don't dare to try out if this works systematically. - Using kernel version 3.13.0-63 and earlier, X starts successfully and I end up with the default display manager. However, trying to log in results in an infinite loop of restarting the display manager. Furthermore, there seems to be a graphics issue: Even though the resolution seems to be standard 1080p, the image does not fill the entire screen area and sometimes the output is totally broken (very large stretch vertically, i.e., streching about 100 pixels over the entire screen plus strange color artifacts) ** Package changed: linux (Ubuntu) => ubuntu ** Changed in: ubuntu Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1516216 Title: X fails to start, starting with kernel version 3.13.0-66 including 3.13.0-68 Status in Ubuntu: Confirmed Bug description: System: Ubuntu 14.04 Graphics Card: Geforce GTX 670 Graphics Driver: nvidia-352.55 Starting with kernel 3.13.0-66, the start of X / default display manager results in a black screen. My observations are: - When I get this black screen, I cannot CTRL+ALT+F1 into a text console - Pressing the power button in this state leads to a proper shutdown (which I guess means that it is not a complete kernel panic). - When using these latest kernel, the graphics behavior during boot-up also has changed. Instead of a graphical animation, the system boots in text mode (I can see the syslog output), and at the moment I should get the display manager, the screen goes black. My work-around so far has been to boot kernel 3.13.0-65 instead of 3.13.0-66, 3.13.0-67, or 3.13.0-68. So far this has worked reliably. However today, booting kernel 3.13.0-65 has resulted in a black screen as well. Fortunately, I found a new work-around: I can boot kernel 3.13.0-68 in recovery mode, and chose simply "continue" in the recovery console. With this modification of the boot process, X will start. In the syslog, I can see some suspicious messages, around the time X should start: "BUG: unable to handle kernel NULL pointer dereference at (null)". I have attached a syslog contain some failed starts as well as a successful one. Another suspicion is that the problem is related having an Oculus Rift DK2 connected. In particular, this requires to use a custom Xorg.conf which runs individual X screens for the main display and the Oculus Rift. --- ApportVersion: 2.14.1-0ubuntu3.18 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: fabian 2526 F.... pulseaudio /dev/snd/controlC0: fabian 2526 F.... pulseaudio CurrentDesktop: Unity DistroRelease: Ubuntu 14.04 HibernationDevice: RESUME=UUID=dfcf8d87-ab70-490e-922d-2ccfd8acdfcc InstallationDate: Installed on 2014-04-24 (569 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417) IwConfig: eth0 no wireless extensions. lo no wireless extensions. MachineType: MSI MS-7816 NonfreeKernelModules: nvidia Package: linux (not installed) ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-68-generic root=UUID=58115c9d-156a-4608-9adb-e20d7ffc9b11 ro recovery nomodeset ProcVersionSignature: Ubuntu 3.13.0-68.111-generic 3.13.11-ckt27 RelatedPackageVersions: linux-restricted-modules-3.13.0-68-generic N/A linux-backports-modules-3.13.0-68-generic N/A linux-firmware 1.127.18 RfKill: Tags: trusty Uname: Linux 3.13.0-68-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo _MarkForUpload: True dmi.bios.date: 05/17/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: V1.2 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: Z87-G43 (MS-7816) dmi.board.vendor: MSI dmi.board.version: 1.0 dmi.chassis.asset.tag: To Be Filled By O.E.M. dmi.chassis.type: 3 dmi.chassis.vendor: MSI dmi.chassis.version: 1.0 dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrV1.2:bd05/17/2013:svnMSI:pnMS-7816:pvr1.0:rvnMSI:rnZ87-G43(MS-7816):rvr1.0:cvnMSI:ct3:cvr1.0: dmi.product.name: MS-7816 dmi.product.version: 1.0 dmi.sys.vendor: MSI To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1516216/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp