cpufreq est and Enhanced Sleep (Cx) States for Intel Core and above

src/sys/i386/cpufreq/est.c has many Pentium M cpus but nothing                                     
from the Intel Core and Core 2 families that I can see.  I tried
looking up the values myself, but could not find them in:
http://www.intel.com/design/mobile/datashts/314078.htm                                             
                                                                                                   
It seems that even the latest version of the Linux kernel does not
list values for at least Yonah (Core 2).  Is it a big mystery, or is
this data actually available somewhere?  I have a Core 2 Duo 
T7600 in my laptop and est won't touch my cpu because it doesn't 
recognize it.  I did get it to use some other form of speed control
by putting hint.acpi_perf.0.disabled="1" in /boot/loader.conf according
to another post.

Another thing I wish could work is the Enhanced cpu Sleep States;
this Dell Latitude D820 laptop only sees C1 although the document
above indicates it should probably support 4 unique states.  Is 
there a way I can debug and/or fix this?  I can post dumps of the
acpi stuff and/or verbose boot logs if it would be helpful.  

Thanks