I appear to have the same problem with my Dell Optiplex desktop machine and my Dell XPS 13 Developer Edition. The XPS is brand new and has been updated to the latest BIOS version. The Optiplex has a somewhat aged BIOS, but I've never seen any problems until now.
Both machines have been updated by doing a clean install of 16.04; Kubuntu on this machine and Ubuntu on the XPS. One thing that I've discovered is that the machine can be pinged when it's down, but otherwise the symptoms are identical to those reported above. Entering coredumpctl returns 'No coredumps found'. The problem has been observed when I am typing, moving the mouse, reading text or simply doing nothing. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/1575467 Title: Ubuntu 16.04 consistently freezes up / hangs Status in linux package in Ubuntu: Confirmed Bug description: After upgrading from stock Ubuntu 14.04 to 16.04 my laptop consistently freezes up and is unresponsive to keyboard or mouse. The only way is to do a hard shutdown. I'm usually in a browser when this happens, and often watching a video or two. It seems to happen more often in Google Chrome than Firefox, but it happens with both. It has happened at least once with no videos loaded. I haven’t observed it freeze / hang when I’m not in a browser, but that's mainly what i use my laptop for, so that's where most of my time is spent. --- ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: andrew 1949 F.... pulseaudio DistroRelease: Ubuntu 16.04 HibernationDevice: RESUME=UUID=e8aaee7c-d956-4519-94f0-cf7aad745020 InstallationDate: Installed on 2015-08-08 (263 days ago) InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1) MachineType: Dell Inc. Inspiron 3451 Package: linux (not installed) ProcEnviron: LANGUAGE=en_US TERM=xterm-256color PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic.efi.signed root=UUID=d01f07be-c906-4024-8eef-a58ba3935298 ro quiet splash vt.handoff=7 ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-4.4.0-21-generic N/A linux-backports-modules-4.4.0-21-generic N/A linux-firmware 1.157 Tags: xenial Uname: Linux 4.4.0-21-generic x86_64 UpgradeStatus: Upgraded to xenial on 2016-04-22 (4 days ago) UserGroups: _MarkForUpload: True dmi.bios.date: 12/05/2014 dmi.bios.vendor: Dell Inc. dmi.bios.version: A00 dmi.board.name: 0H4MK6 dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 8 dmi.chassis.vendor: Dell Inc. dmi.chassis.version: Not Specified dmi.modalias: dmi:bvnDellInc.:bvrA00:bd12/05/2014:svnDellInc.:pnInspiron3451:pvrA00:rvnDellInc.:rn0H4MK6:rvrA00:cvnDellInc.:ct8:cvrNotSpecified: dmi.product.name: Inspiron 3451 dmi.product.version: A00 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1575467/+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