16.04 on Dell Precision shuts down during suspend if AC is unplugged

[Simon Kuang]

My Dell Precision 5510 laptop has recent drivers for graphics. I installed a lot of updates this week, and I have been finding that the laptop shuts down in the "Suspend" state if at any point AC power is unplugged.

Steps to reproduce:
1. With laptop plugged in to AC power and Ubuntu running, use the GUI to enter the suspend state.
2. With the laptop suspended, unplug AC power.
3. Plug in AC power again.
4. Press the ACPI power button to trigger a wake from suspend.

Expected behavior:
Login screen to resume the pre-suspend session.

Actual behavior:
Laptop goes through POST. During startup, fsck-like text flashes on the screen indicating that a "hard shutdown" occurred.

What I've done:
(I boot with GRUB from an encrypted LVM partition.) My grub config already has the "acpi_sleep=nonvs" option from the last time I had a suspend-related issue. Most online fora will recommend this as a fix, but I am still having these problems. I even re-ran grub-update just to be sure.

uname -a output:
Linux simon-Precision-5510 4.4.0-142-generic #168-Ubuntu SMP Wed Jan 16 21:00:45 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-142-generic 4.4.0-142.168
ProcVersionSignature: Ubuntu 4.4.0-142.168-generic 4.4.167
Uname: Linux 4.4.0-142-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: simon 3648 F.... pulseaudio
CurrentDesktop: Unity
Date: Mon Feb 11 15:40:27 2019
HibernationDevice: RESUME=UUID=1c08d766-1118-4cc3-90dc-7671d83d7ae0
InstallationDate: Installed on 2016-06-23 (963 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 04f3:21d5 Elan Microelectronics Corp.
 Bus 001 Device 002: ID 8087:0a2b Intel Corp.
 Bus 001 Device 004: ID 0c45:6713 Microdia
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Dell Inc. Precision 5510
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-142-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro acpi_sleep=nonvs quiet splash acpi_sleep=nonvs vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-142-generic N/A
 linux-backports-modules-4.4.0-142-generic N/A
 linux-firmware 1.157.21
SourcePackage: linux
UpgradeStatus: Upgraded to xenial on 2019-01-05 (37 days ago)
dmi.bios.date: 04/07/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 01.02.00
dmi.board.name: 0N8J4R
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr01.02.00:bd04/07/2016:svnDellInc.:pnPrecision5510:pvr:rvnDellInc.:rn0N8J4R:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Precision 5510
dmi.sys.vendor: Dell Inc.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Anthony Wong (anthonywong)]

Are you able to find the last known good kernel in grub and boot into it to see if the problem exist? Please also reproduce the problem and attach your /var/log/kern.log to this bug in your next reboot. Thanks.

[Simon Kuang (simontheflutist)]

The problem has mysteriously resolved itself.

I updated once again yesterday via Software Updater (for good measure). I haven't changed any settings; kernel is still 4.4. Based on some Googling it seems the problem might have been related to some part of my system which is hallucinating mid-sleep that the battery is out. I'm honestly not sure what happened, and I'm not sure if I am willing or even able to reproduce the bug.