patch: p4tcc and speedstep cpufreq drivers

[Nate Lawson]

Kevin Oberman wrote:
> OK. This makes me feel a bit better, but I still think I'll leave TCC
> out of the equation as it makes the various frequency steps vary uneven
> to the point that lowering dev.cpu.0.freq would increase performance
> (and the reverse, as well) and it causes my system to hang when
> throttled back too far. It never hangs with TCC disabled although my
> lowest "frequency" is now just 150 MHz.

Would you test with hint.acpi_throttle.0.disabled="1" instead of 
disabling p4tcc?  I think p4tcc is not the problem, it's the combination 
of the two.  I think there are some problems when both the chipset 
(externally) and processor (internally) assert STOPCLOCK.  If this works 
for you with no hangs, I'll commit code to disable acpi_throttle when 
p4tcc is present.  p4tcc is more efficient than acpi_throttle since the 
latter is done through the chipset, giving more chance for race 
conditions, latency, etc.

-- 
Nate