There was indeed a regression between 3.13.0-26 and 3.13.0-27. And between 3.13.0-28 and 3.13.0-29 if you've installed AceLan's 3.13.0-28 kernel.
By the way, the bug hasn't been fixed yet in the official kernel, but it's been taken care of. See https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1305522 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1218973 Title: [Dell XPS 12-9Q33] Touchpad not recognized To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1218973/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs