Thinkpad T530 fails to suspend after 2-3 cycles when watchdog service is enabled

[Michael Marley]

On my Thinkpad T530 laptop, if I install and enable the watchdog service with the iTCO_wdt watchdog device, suspend stops working correctly. It always works correctly the first time, but if I try 2 or 3 times, it often locks up and fails to go into suspend on the second or third attempt. If I disable the watchdog service, suspend works perfectly no matter how many times I try.

I followed the instructions at https://wiki.ubuntu.com/DebuggingKernelSuspend and the result is "memory memory48: hash matches".

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: watchdog 5.14-3 [modified: lib/systemd/system/watchdog.service]
ProcVersionSignature: Ubuntu 4.4.0-14.30-lowlatency 4.4.5
Uname: Linux 4.4.0-14-lowlatency x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CurrentDesktop: KDE
Date: Sat Mar 19 10:30:19 2016
InstallationDate: Installed on 2014-06-01 (656 days ago)
InstallationMedia: Kubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.1)
SourcePackage: watchdog
UpgradeStatus: No upgrade log present (probably fresh install)
mtime.conffile..etc.watchdog.conf: 2015-09-05T09:54:44.925151