Hi,
I have a brand new XPS 15 (9550) machine which I suppose may have a factory defect, but I'd like to try asking here and see if others have similar experiences before sending it to repair.
TL;DR; Issuing a shut down, hibernate or start command makes the laptop go down. Light from the power button goes away. 2 seconds later, the power comes back on and the system starts up.
On delivery, the laptop had Win 10 Pro on it. I want to have a clean install without the bloatware which is often shipped with new computers, so I reinstalled it on the very first day with a USB stick prepared with Windows 10 Pro install media on it. Once installed, I added the WLAN driver and let the machine get all other drivers via Windows update. Once done, I shut down the machine and put it in my bag. So far so good, I thought.
When i took it of of my bag I instantly noticed that it was hot and that the screen was already at the Windows logon as soon as I flipped up the screen. Logged on and tried to shut it down just to realize that the machine comes back on 2 seconds after completed shut down. I tried this several times to see if it was repeatable, and yes it is. Behavior is same every time. It's the same regardless of choosing shut down, hibernate or sleep. Always 2 seconds after the light on power button goes out, power comes back on.
BIOS wise, 1.2.10 or 1.2.14 release behaves equal. I have tried resetting the BIOS to factory defaults and BIOS defaults as well.
Operating system wise, I've tried reinstalling the machine with both the Microsoft install image (The Microsoft tool that prepares a USB drive as Win 10 installation media) and the image supplied by Dell via the support pages. No difference. I've tried to stay on drivers supplied by Windows update, as well as manually installing everything from Dell support site. No difference. Findings from google refer to "Fast boot" setting in windows but I did not get any improvement from either settings of this.
I even went as far as tried to run Ubuntu on the laptop to see if the behavior is OS agnostic, and yes it seems. Shut down from the menu of the Ubuntu desktop gives the same result. 2 seconds after power led goes out, the power returns.
Even when in the BIOS settings menu, I can do a short press of the power button to request a shut down and reach the same result. 2 seconds after power led coming off, system is by itself restarting.
The only way to shut down this computer is to do a long press on the power button. If I do that, the machine shuts down and stays off.
Last thing to share here is that inside the BIOS interface, there is a power state log. In there I can see that the system has powered off at a certain timestamp and that the associated reason is something like "ACPI Power off" or similar (don't have the machine here at hand right now". Immediately after that, there is a power on event but the reason is listed as "Not applicable". I interpret this that there is something actually making a signal to the system to start up, rather than a hardware fault. Possibly a BIOS bug.
My patience is rather much consumed with this as I do not see any more things to try. I think next stop is the workshop for this machine but I cannot be without it for the next week so I'll need to keep it with me some time still.