Comment 6 for bug 1349740

Having this problem myself on Acer Aspire E5-511. Can't poweroff (but can halt) and there are a few suspect dmesg entries for a cause, but it may help lead to a solution, assuming the upcming 3.18 kernel won't hold great untold treasures of course!

See bug report upstream https://bugzilla.kernel.org/show_bug.cgi?id=85931