Comment 33 for bug 1401943

Utopic will pick up the fix when it gets the 3.16.7-ckt2 updates. Those updates have now been applied to the -proposed repository. Would it be possible for you to test this latest kernel and post back if it resolves this bug?
See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

Thank you in advance!