After selecting “Suspend” from the session dialog, the computer goes to sleep and wakes up on its own a few seconds later.
Probably cause it network adapter hardware, driver or firmware.
- Unplugged USB mouse, keyboard and network cable
- Restarted PC
- Checked system log -> does not indicate what woke the computer up (“ACPI: Low-level resume complete”)
- Checked suspend log -> /var/log/pm-suspend.log
- Disabled wake up capable devices
- List wake up capable devices -> acpitool -w
- Disable particular device -> acpitool -W [Device No.]
- In my case, disabled GLAN, EHC1, EHC2, & HXC
- Removed e1000e module, shutdown VirtualBox virtual machines (Win 8.1 IE 11 Virtual Machine may be a cause), then re-added the module
- sudo rmmod e1000e
- double-check that GLAN is still disabled with acpitool -w
- Computer will now sleep without waking up.
- sudo modprobe e1000e
- Re-enable wake up devices with acpitool -W [Device No.]
- Restarted computer. Launched various apps (Chrome, Firefox, Virtual Box + VMs) and tried to suspend PC. Works for now.