Re: Linux 2.4.19-rc1-ac3

Dominik Brodowski (devel@brodo.de)
Sun, 14 Jul 2002 17:50:25 +0200


On Sun, Jul 14, 2002 at 05:19:54PM +0200, Peter Osterlund wrote:
> Dominik Brodowski <devel@brodo.de> writes:
>
> I tried speedstep but it didn't work because of this check in
> speedstep_detect_processor:
>
> /* Intel Pentium 4 Mobile P4-M */
> if (c->x86_model != 2)
> return 0;
>
> if (c->x86_mask != 4)
> return 0; /* all those seem to support Enhanced
> SpeedStep */
>
> My cpu has model == 1 and mask == 2.
Strange: According to the Intel docs (24919923.pdf and 25072104.pdf) as of
June 2002, all P4-Ms have models have model "2" and mask "4", and none have
model "1" and mask "2". What does /proc/cpuinfo say? And are you really sure
it is a speedstep-capable P4-M?

I'm really doubtful of that, as the MSR_EBC_FREQUENCY_ID didn't change a bit
while trying speedstep transitions:

> cpufreq: P4 - MSR_EBC_FREQUENCY_ID: 0x8a01fe00 0x0
<snip>
> cpufreq: P4 - MSR_EBC_FREQUENCY_ID: 0x8a01fe00 0x0

> cpufreq: currently at low speed setting - 13800 MHz
Obviously, this value is bogus, what's the correct CPU frequency of your
notebook?

> So what can I do to make speedstep work? According to the notebook
> manual, speedstep is supported on this computer.
How old is it? Fresh-out-of-the-factory? Then there might, just might be
some update to the P4 specifications not yet included in the documentation.
And please send me a /proc/cpuinfo, just to make sure. And, BTW, have you
tried ACPI and its "performance state" interface?

Dominik
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