Alexander Kops, to advise, posting small snips of syslog, or any log for that matter, isn't helpful, as what you posted could be a result of some other issue earlier in the log. Instead, you would want to post the log in its entirety, and advise when in the log you performed an action correlated to the problem. In this case, the event most correlated to your computer improperly shutting down is the act of locking it.
With this in mind, I'd like to follow up on your comment: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1727662/comments/8 >"Yes, I think it only happens after suspend though." It needs to be confirmed without doubt via you checking the GUI settings that your computer is set after you lock the screen that it will only turn off the monitor, only suspend, or turn off the monitor first, then some time after this event, it goes into suspend, etc. Could you please advise to which situation precisely is the case? Also, with issues like these, folks typically update their buggy, outdated, and insecure BIOS prior to reporting, as BIOS bugs can manifest issues like this. As per your dmesg: https://launchpadlibrarian.net/343008378/CurrentDmesg.txt [ 0.000000] [Firmware Bug]: TSC_DEADLINE disabled due to Errata; please update microcode to version: 0x25 (or later) ... [ 0.120112] pnp 00:01: [Firmware Bug]: PNP resource [mem 0xfed10000-0xfed13fff] covers only part of 0000:00:00.0 Intel MCH; extending to [mem 0xfed10000-0xfed17fff] In addition, there are numerous BIOS bugs fixed as identified by Lenovo: https://pcsupport.lenovo.com/us/en/products/LAPTOPS-AND-NETBOOKS/THINKPAD-T-SERIES-LAPTOPS/THINKPAD-T450S/downloads/DS102110 Once updated, could you please post the result of the following terminal command: sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date -- 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/1727662 Title: Crashes after unlock: [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun Status in linux package in Ubuntu: Incomplete Bug description: After upgrading from Ubtuntu 17.04 to Ubuntu 17.10 this bug started appearing. When I lock my screen on my Lenovo T450s and the notebook sits in the dock (two external screens attached), one of the three things happen when I come back after some time and try to unlock (so it went to power save in-between): * Most of the time the computer was just shut down and I have to start it again * Sometimes the notebook screen flickers weirdly and one of the two other screens show pixel garbage * The notebook screen shows the lock screen but is completely frozen. Occasionally unlocking also works. The last thing I find in /var/log/syslog is [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun Using or not using the following kernel parameter didn't change anything: i915.enable_rc6=0 ProblemType: Bug DistroRelease: Ubuntu 17.10 Package: linux-image-4.13.0-16-lowlatency 4.13.0-16.19 ProcVersionSignature: Ubuntu 4.13.0-16.19-lowlatency 4.13.4 Uname: Linux 4.13.0-16-lowlatency x86_64 ApportVersion: 2.20.7-0ubuntu3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: akops 3337 F.... pulseaudio /dev/snd/controlC0: akops 3337 F.... pulseaudio CurrentDesktop: ubuntu:GNOME Date: Thu Oct 26 10:44:11 2017 HibernationDevice: RESUME=/dev/mapper/system-swap_1 MachineType: LENOVO 20BWS2YL00 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.13.0-16-lowlatency root=/dev/mapper/system-root ro quiet splash i915.enable_rc6=0 crashkernel=384M-:128M vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-4.13.0-16-lowlatency N/A linux-backports-modules-4.13.0-16-lowlatency N/A linux-firmware 1.169 SourcePackage: linux UpgradeStatus: Upgraded to artful on 2017-10-20 (5 days ago) dmi.bios.date: 07/08/2015 dmi.bios.vendor: LENOVO dmi.bios.version: JBET51WW (1.16 ) dmi.board.asset.tag: Not Available dmi.board.name: 20BWS2YL00 dmi.board.vendor: LENOVO dmi.board.version: SDK0E50510 WIN dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrJBET51WW(1.16):bd07/08/2015:svnLENOVO:pn20BWS2YL00:pvrThinkPadT450s:rvnLENOVO:rn20BWS2YL00:rvrSDK0E50510WIN:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad T450s dmi.product.name: 20BWS2YL00 dmi.product.version: ThinkPad T450s dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1727662/+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