Comment 34 for bug 1529381

So it's highly likely that the 64 bit addresses used for specific PM registers are wrong in the FADT, where as they are correct in the 32 bit addresses.

The FADT supports old 32 bit legacy addressing for PM registers and 64 bit addressing too. Unfortunately sometimes the firmware sets the 64 bit versions incorrectly and the kernel is now using these in preference to the 32 bit variant, hence the issue.