Hardware: lenovo g 780; software: opensuse tumbleweed with kernel 3.12-rc3. After going to sleep mode and waking up console at alt+F# is flooding with messages like [600.000000] alx 0000:02:00.0: invalid PHY speed/duplex: 0xffff You can't leave console after switching to it, the only way to reboot is to hold power button for 4 seconds.
After waking up from sleep apart from these messages laptop can't go again to sleep, presumably because of this bug.
*** This bug has been marked as a duplicate of bug 62491 ***