This thread had many suggestions that look like good leads for you to follow up with.
Things to try
idea #1 - systemd
If your system uses systemd try using this:
idea #2 - blacklist kernel module mei_me
$ systemctl poweroff
idea #3 - interrogate journalctl boot messages
This mei_me ( Intel Management Engine Interface) for Mobile Intel Express Chipset, causes a lot of trouble.
You can blacklist the module, you could lose functionality that I'm not aware of.
If your laptop supports it you may be able to disable it in your BIOS.
I read people having success disabling it, though their all different issues.
Take a look at the
journalctl for feedback on what's causing the system to reboot.
idea #4 - Add kernel parameter acpi=force
$ sudo journalctl -b
Try adding the following to your kernel's boot parameters. These can be appended to the end of your kernel's line in
idea #5 - Try a different power supply (larger rated)
linux /vmlinuz-3.14.4-100.fc19.x86_64 root=/dev/mapper/fedora_greeneggs-root ro rd.md=0 ... acpi=force ...
idea #6 - disable WOL (Wake On LAN)
My power supply was 450W. However, I got tired of going around the head until I read on page 23 of the GA-Z87N-WIFI manual which case we use the PCI-E was advisable to use a power supply of 500W or higher, as lower springs would destabilize (possible cause of the reboot).
Made to upgrade to a 650W power supply and reboots after shutdown, never happened.
Conclusion: new graphics cards are hungry for energy. Always check the power requirements of the printing and adjust energy sources.
idea #7 - bug in kernel with xhci module
By default, the Wake-up LAN is enabled in BIOS (Power Manegement). As I have a Synology NAS configured for my private network, the "trickster" is sending packets to the network and enables me to Linux machine after doing this shutdown.
I followed your recommendation (I disabled the Wake-up LAN) and everything works as expected.
xhci: Fix spurious wakeups after S5 on Haswell
Source Bug 66171 - [PATCH]Poweroff doesn't work, it just reboots