Hey dev types,
For the longest time, the onboard DMP that powers the MPU-9150 was only doing 6-axis fusion. Not sure what happened, but after a couple acquisition of some patent companies, out pops the Embedded Driver Library 6.0 which now does 9-axis on chip.
My hope is that this now takes care of a lot of the extra work with the compass that we have had to do. In the past the algorithms that InvenSense has been using to do fusion have seemed really good.
If you have any time and interest, porting our solution to the new library is an open task.