Re: speedstep-centrino on dothan

[Pedro Ramalhais <ramalhais@serrado.net>]

st3@riseup.net wrote:
> Currently, the speedstep-centrino support has built-in frequency/voltage
> pairs only for Banias CPUs. For Dothan CPUs, these tables are read from
> BIOS ACPI.
> 
> But ACPI encoding may not be available or not reliable, so why shouldn't we
> provide built-in tables for Dothan CPUs, too? Intel has released this
> datasheet:
> 
> http://www.intel.com/design/mobile/datashts/302189.htm
> 
> with frequency/voltage pairs for every version of Dothan CPUs.
> 
> Moreover, I checked on Pentium M 725 and Pentium M 715 that the lowest
> frequency at which the CPU can be set safely is not the 600MHz given in
> datasheets, but 400MHz instead, with VID#A, VID#B, VID#C and VID#D (see
> datasheet for more details) set to 0.908V.
> 
> I can provide a patch, let me know.
> 
> 
> --
> ciao
> st3
> 

I looked into it 2 weeks ago, and i couldn't find a complete voltage
table for the Dothan C1 stepping (which my laptop has). I only found a
table with (IIRC) the max and min voltages for the max and min
frequencies. I also didn't understand the meaning of the different
VID#{A,B,C,D,E} values. Are these voltages related to the quality of the
power supply, or the quality of the processor? How do we know which one
to choose?

Regards,
--
Pedro Ramalhais

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