Setting for retrieving raw data

All i want to do is retrieve raw data from the accel,gyro and mag. what are the setting that i have to have to do this ? and what step do i have to do in my code after? according to this post http://diydrones.com/profiles/blogs/secrets-of-the-mpu9150
"The I2C passthrough didn't work. Only using dual I2C busses connected to the mane I2C & the aux I2C worked. The mane I2C reads the gyro & accel. The aux I2C reads the mag.

The real problem is if you simply read the gyro & accel registers, you'll always get the same value. They tried & failed to synchronize the register refreshes with inactivity on the I2C bus."

I do not understand this can someone please explain? And check this post for correctness.

What is aux I2c vs mane i2c?

Thank you