Skylake (XHCI): System self start just after suspend S3.

[Jose Trujillo]

Dear coreboot engineers:

My Skylake system S3 suspension fails because it wakes up immediately.

If I connect the keyboard and mouse to USB2 ports and remove all USB devices from the USB3 ports then USB wake up works correctly until I connect something in the USB3 ports.
If I disable XHCI as wake up source in linux can go to S3 state but USB wake up no longer works.

Could it be missing configuration / ASL code?... a bug?
Do somebody knows how to make it work correctly?
Thank you,
Jose Trujillo.