Comment 8 for bug 93331

That appears to be a Dothan core. My cpuinfo shows (same family & model, different frequency):

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 1.60GHz
stepping : 6
cpu MHz : 600.051
cache size : 2048 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe up est tm2
bogomips : 1201.24
clflush size : 64

Frequency scaling used to work with speedstep-centrino, up to and including Edge (kernel 2.6.17). I _think_ it worked with 2.6.18, early on in the Feisty development cycle, but it hasn't worked with any of the 2.6.19 or 2.6.20 kernels. Since the Dothan freq/voltage pairs have never been officially coded into speedstep-centrino, I can only presume that it obtained them via ACPI (still using the speedstep-centrino driver however).

Since the ACPI code in speedstep-centrino was deprecated, and copied to acpi-cpufreq, it hasn't worked. The acpi-cpufreq module does not work either. This is really frustrating - not only does my notebook fan never turn off now, but the CPU is stuck running at 600MHz, instead of floating between 600MHz and 1.6GHz.

I've also opened a bug on bugzilla.kernel.org: http://bugzilla.kernel.org/show_bug.cgi?id=8245