(Just FYI to everyone out there, since this is not easy to find right now.)
If you’re seeing this message:
mpt2sas0: log_info (0x31080000): original (PL), code (0x08), sub_code (0x0000)
Then you need to visit http://mycusthelp.info/LSI/_cs/AnswerDetail.aspx?&inc=8484
The short answer: Avago Tech (which acquired LSI in 2014) performed a stealth update to the P20 driver .zip artifacts on 21-MAY-2015. Re-download the P20 .zip that contains the firmware (the xxxx_P20_IR_IT_Firmware_BIOS_for_MSDOS_Windows downloads contain the firmware .bin file), and upgrade your LSI firmware to the 20.00.04.00 version. Sadly, neither the .zip nor the .bin are named that way.