Comment 11 for bug 751689

@Andy, as stated, this is not a change in behavior-- maverick had the same problem of not spinning the fan high enough (only 4500rpm) when temperatures were particularly high. The difference between maverick and natty is that maverick tends to run ~8C cooler so you hit the critical 100C shutdown less frequently (but still hit it).

The BIOS/EC should be handling this, and indeed it does adjust the fan speed between 0 and 4500rpm just fine. The problem is that it doesn't spin up the fans to a fast enough speed (they are capable of ~6500rpm) when under very high temperatures. Also, when Advanced Thermal Management in the BIOS is set to 'Maximum Performance' (the apparent default for this machine when on AC) the problem is especially aggravated since frequency scaling doesn't seem to occur. When Advanced Thermal Management is set to 'Balanced' (the default when on battery), cpu frequency scaling does occur, which helps with overheating but there are still cases where the CPUs are at their lowest frequency and the fans at their BIOS/EC maximum speed (ie 4500rpm) where the temperature still goes up and you hit 100C.

I have an up to date BIOS/EC according to the Lenovo website. The 'Maximum Performance' vs 'Balanced' might be as designed, but clearly there is a problem when the lowest cpu frequency and the highest fan rpm in the default install is not enough to keep the machine from hitting 100C. While the fix should probably be with Lenovo, perhaps there is something we could do in the driver when i7s hit 85C we should spin up to level 7 (otoh solution).