Many PIR tables on many platforms are just flat-out wrong. As mentioned here in earlier years, something like 50% of the geode platforms out there had incorrect PIR tables, and Linux had incorrect interpretation of those tables inserted which made the 1/2 boards that were working break (this was all 10 years ago)
Why is it not fixed? Because, nowadays, the thing you're supposed to use is the ACPI table. We've seen cases where both PIR and _MP_ were copied from a different motherboard, with no change, and were completely wrong. It's obvious that most vendors don't care to take the time to make these tables right. ron