Spurious thermal shutdowns on Dell Studio 1557

[Bartosz Fabianowski]

> If you still have old kernel, you can try booting it and looking at
> the system performance with some kind of CPU-bound benchmark.

Unfortunately, the old kernel is long gone.

> Theoretically, your laptop should be able to run with CPU stuck at
> its highest frequency without shutting down.

I agree. This is precisely what I am trying to achieve.

> ISTR there are few CPU frequency drivers that could use some
> disabling.

Disabling p4tcc changed nothing. Disabling apci_throttle as well finally 
reduced the frequencies from 13 to 6. I have yet to see what effect this 
will have on system performance.

> Does 'hw.acpi.thermal.tz1.active' show value of '0' an this point?
> Does it go back to '1' when temperature drops below 71C? Does it ever
> show '-1'?

The value varies between 0 and 1. When the machine is idling, 
temperature tends to drop to 55°C and then hover there. As this is 
exactly the lowest _ACx threshold, active stays at 0.

Just as I was writing this e-mail, the temperature finally reached 54°C 
and active went to -1. The fan is still on, however.

- Bartosz