[SOLVED] Suspend Skylake Fatal1ty z170 gaming-itx

Some news about the issue:
- good news: the TSC/HPET issue is solved with BIOS 2.30b
- bad news: I still got the reboot after the second wake-up

What was really strange is that Asrock tested my build in their facilities, and manage to reproduce the problem in some circumstances :
- old BIOS + install OS (Debian) + flash BIOS => reboot at 2nd wake-up
- new bIOS + install OS (Ubuntu or Win10) => no reboot at 2nd wake-up

So they erased my hard-drive, and installed Ubuntu + Win10 on it, verified that it works and ship it back to me.

As soon as it arrived, I made an image of the hard-drive before even booting it (to keep the state intact).
Then I started Ubuntu and I got the reboot at 2nd wake-up ! :-(
Then I started Win10 and I got the reboot at 2nd wake-up ! :-(

I've tried switching the external power supply, changing the mini-ITX case, changing the display, changing the display cable, changing keyboard (USB and PS/2) but I still have the problem.
I even made a movie of myself doing the test to check with Asrock that I am doing exactly like they were doing.

We are running out of idea and I may ship my computer back again to Asrock to solve this mystery, once and for all.

The good news is that I found out that waking-up the computer through the keyboard instead of the mini-itx power button, manage to wake-up the computer without problem every single time.
However since I am using a wireless keyboard, I cannot use this workaround in my particular case, but it could be useful for others.

Anyone has an idea why it worked at Asrock office and can not work at my home ?

Anyway big thanks to Asrock, the support was really great !

Jessie wrote: With Asrock, we finally managed to nail the problem: the power button has to be pushed very quickly. I don't know why (it wasn't a problem with other motherboard) but pushing it and maintaining it a bit longer (but less than a second) trigger the reboot. So people having trouble resuming from suspend, try to push the button faster !

That could be caused by the PC case power button, for several reasons. I've seen power buttons "stick" in the pressed/on position. Does your button move from the pressed/down position back to  the unpressed/up position quickly? What PC case are you using?

Also, the power button may be partially worn out or damaged. When pressed firmly, it is sending two signals to the mother board, on-off-on, or while the button seems to be released and not "on", it still is sending the "on" signal to the board. If you pressed down and held the power button down when the PC is in Sleep mode, what does it do?

Just because the power button worked fine with another board, does not mean it is working perfectly fine now. Things can break at any time for no apparent reason.

The power button on PC cases is not like a regular power switch, like a light switch. The only time the PC case power button circuit is closed or on, is when the button is pressed down. That causes the board to "see" that change in the circuit, which then sends a signal to the PSU to turn on. When the PC power button is released/not pressed, the power button circuit is open or off. It seems as if the PC power button is sending multiple on/closed signals to the board very quickly, one after another.