Understanding training patterns for Stratix-II deserializer DPA

FvM,

I started by using common sense and common knowledge very similar to yours and ended up in where I am now, which, believe me, is not a pleasant place to be. So from now on I want to rely on exact knowledge, preferably directly from the developers of the DPA module in Stratix-II or, at worst, from somebody who can talk to them.

Who knows, may be they cut some corner or simply made a mistake and, as a result, DPA do requires strictly periodic patterns for proper delay tracking?