Speedstep-centrino problems

Speedstep-centrino problems

[Simon Moore]

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Hi,

I'm trying to get acpi cpu throttling working for my Dell Inspiron 510m
with a Pentium M Centrino 1.6 Ghz cpu.

I have tried a number of possibilites but have not got anywhere. I have
an open case over at the gentoo forums but we have not had success in
resolving this problem.

This is my last ditch attempt to try and find a solution to this
problem. I think I have exhausted most possible avenues so I'm trying to
get some kernel hacker on board and help me with this.

I would very much appreciate it if someone could take a look at this
thread and possbily come up with a suggestion of what might be causing
this. (http://forums.gentoo.org/viewtopic.php?p=2076710) I have a lot of
info in that thread that you should find useful but if there's any other
info you require I'll post it tonight.

For what it's worth I hope it intrigues some of you enough to help me
out.

Thanks all the same,

Regards,

Saimon


--------------------------
Saimon Moore
Departamento TI
CondisLine e-Commerce S.A.

telf./fax: 93 565 3400 ext. 473 / 935752325
http://www.condisline.com
mailto://simon_moore-HnN13UdsTkzz1n+OaKNE4w@public.gmane.org 


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Re: Speedstep-centrino problems

[Galin Yordanov]

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Hello,

I have Acer TM4500 with Centrino 1.6 (Dothan)and i had the same problem ..
then i found this patch (attached), cannot remember where i found it but it 
works ;)

Regards,
Galin
On Thursday 10 February 2005 04:38 am, Simon Moore wrote:
> Hi,
>
> I'm trying to get acpi cpu throttling working for my Dell Inspiron 510m
> with a Pentium M Centrino 1.6 Ghz cpu.
>
> I have tried a number of possibilites but have not got anywhere. I have
> an open case over at the gentoo forums but we have not had success in
> resolving this problem.
>
> This is my last ditch attempt to try and find a solution to this
> problem. I think I have exhausted most possible avenues so I'm trying to
> get some kernel hacker on board and help me with this.
>
> I would very much appreciate it if someone could take a look at this
> thread and possbily come up with a suggestion of what might be causing
> this. (http://forums.gentoo.org/viewtopic.php?p=2076710) I have a lot of
> info in that thread that you should find useful but if there's any other
> info you require I'll post it tonight.
>
> For what it's worth I hope it intrigues some of you enough to help me
> out.
>
> Thanks all the same,
>
> Regards,
>
> Saimon
>
>
> --------------------------
> Saimon Moore
> Departamento TI
> CondisLine e-Commerce S.A.
>
> telf./fax: 93 565 3400 ext. 473 / 935752325
> http://www.condisline.com
> mailto://simon_moore-HnN13UdsTkzz1n+OaKNE4w@public.gmane.org

-- 
[In Linux We Trust]
Galin Yordanov
galin-Dn6zUBO643CDvotElmWtJA@public.gmane.org

[-- Attachment #2: 03-cpufreq-speedstep-dothan-3.patch --]
[-- Type: text/x-diff, Size: 3670 bytes --]

--- ./arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c.orig	2004-08-06 18:42:15.000000000 +0800
+++ ./arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c	2004-08-06 18:44:28.000000000 +0800
@@ -195,6 +195,82 @@
 	OP(1700, 1484),
 	{ .frequency = CPUFREQ_TABLE_END }
 };
+
+#undef OP
+
+/* Dothan processor datasheet 30218903.pdf defines 4 voltages for each
+   frequency (VID#A through VID#D) - this macro allows us to define all
+   of these but we only use the VID#C voltages at compile time - this may
+   need some work if we want to select the voltage profile at runtime. */
+
+#define OP(mhz, mva, mvb, mvc, mvd)					\
+	{								\
+		.frequency = (mhz) * 1000,				\
+		.index = (((mhz)/100) << 8) | ((mvc - 700) / 16)       	\
+	}
+
+/* Intel Pentium M processor 715 / 1.50GHz (Dothan) */
+static struct cpufreq_frequency_table dothan_1500[] =
+{
+	OP( 600,  988,  988,  988,  988),
+	OP( 800, 1068, 1068, 1068, 1052),
+	OP(1000, 1148, 1148, 1132, 1116),
+	OP(1200, 1228, 1212, 1212, 1180),
+	OP(1500, 1340, 1324, 1308, 1276),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 725 / 1.60GHz (Dothan) */
+static struct cpufreq_frequency_table dothan_1600[] =
+{
+	OP( 600,  988,  988,  988,  988),
+	OP( 800, 1068, 1068, 1052, 1052),
+	OP(1000, 1132, 1132, 1116, 1116),
+	OP(1200, 1212, 1196, 1180, 1164),
+	OP(1400, 1276, 1260, 1244, 1228),
+	OP(1600, 1340, 1324, 1308, 1276),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 735 / 1.70GHz (Dothan) */
+static struct cpufreq_frequency_table dothan_1700[] =
+{
+	OP( 600,  988,  988,  988,  988),
+	OP( 800, 1052, 1052, 1052, 1052),
+	OP(1000, 1116, 1116, 1116, 1100),
+	OP(1200, 1180, 1180, 1164, 1148),
+	OP(1400, 1244, 1244, 1228, 1212),
+	OP(1700, 1340, 1324, 1308, 1276),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 745 / 1.80GHz (Dothan) */
+static struct cpufreq_frequency_table dothan_1800[] =
+{
+	OP( 600,  988,  988,  988,  988),
+	OP( 800, 1052, 1052, 1052, 1036),
+	OP(1000, 1116, 1100, 1100, 1084),
+	OP(1200, 1164, 1164, 1148, 1132),
+	OP(1400, 1228, 1212, 1212, 1180),
+	OP(1600, 1292, 1276, 1260, 1228),
+	OP(1800, 1340, 1324, 1308, 1276),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 755 / 2.00GHz (Dothan) */
+static struct cpufreq_frequency_table dothan_2000[] =
+{
+	OP( 600,  988,  988,  988,  988),
+	OP( 800, 1052, 1036, 1036, 1036),
+	OP(1000, 1100, 1084, 1084, 1084),
+	OP(1200, 1148, 1132, 1132, 1116),
+	OP(1400, 1196, 1180, 1180, 1164),
+	OP(1600, 1244, 1228, 1228, 1196),
+	OP(1800, 1292, 1276, 1276, 1244),
+	OP(2000, 1340, 1324, 1308, 1276),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
 #undef OP
 
 #define _BANIAS(cpuid, max, name)	\
@@ -205,6 +281,13 @@
 }
 #define BANIAS(max)	_BANIAS(&cpu_ids[CPU_BANIAS], max, #max)
 
+#define DOTHAN(cpuid, max, name)	\
+{	.cpu_id		= cpuid,	\
+	.model_name	= "Intel(R) Pentium(R) M processor " name "GHz", \
+	.max_freq	= (max)*1000,	\
+	.op_points	= dothan_##max,	\
+}
+
 /* CPU models, their operating frequency range, and freq/voltage
    operating points */
 static struct cpu_model models[] =
@@ -218,6 +301,11 @@
 	BANIAS(1500),
 	BANIAS(1600),
 	BANIAS(1700),
+	DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1500, "1.50"),
+	DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1600, "1.60"),
+	DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1700, "1.70"),
+	DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1800, "1.80"),
+	DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 2000, "2.00"),
 
 	/* NULL model_name is a wildcard */
 	{ &cpu_ids[CPU_DOTHAN_A1], NULL, 0, NULL },
@@ -227,6 +315,7 @@
 };
 #undef _BANIAS
 #undef BANIAS
+#undef DOTHAN
 
 static int centrino_cpu_init_table(struct cpufreq_policy *policy)
 {

RE: Speedstep-centrino problems

[Simon Moore]

Thanks, I'll try it out tonight and let you know...

Much appreciated... :)

Best regards,

Saimon

> -----Mensaje original-----
> De: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org 
> [mailto:acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org] En nombre de 
> Galin Yordanov
> Enviado el: jueves, 10 de febrero de 2005 12:30
> Para: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> Asunto: Re: [ACPI] Speedstep-centrino problems
> 
> 
> Hello,
> 
> I have Acer TM4500 with Centrino 1.6 (Dothan)and i had the 
> same problem .. then i found this patch (attached), cannot 
> remember where i found it but it 
> works ;)
> 
> Regards,
> Galin
> On Thursday 10 February 2005 04:38 am, Simon Moore wrote:
> > Hi,
> >
> > I'm trying to get acpi cpu throttling working for my Dell Inspiron 
> > 510m with a Pentium M Centrino 1.6 Ghz cpu.
> >
> > I have tried a number of possibilites but have not got anywhere. I 
> > have an open case over at the gentoo forums but we have not had 
> > success in resolving this problem.
> >
> > This is my last ditch attempt to try and find a solution to this 
> > problem. I think I have exhausted most possible avenues so 
> I'm trying 
> > to get some kernel hacker on board and help me with this.
> >
> > I would very much appreciate it if someone could take a 
> look at this 
> > thread and possbily come up with a suggestion of what might 
> be causing 
> > this. (http://forums.gentoo.org/viewtopic.php?p=2076710) I 
> have a lot 
> > of info in that thread that you should find useful but if 
> there's any 
> > other info you require I'll post it tonight.
> >
> > For what it's worth I hope it intrigues some of you enough 
> to help me 
> > out.
> >
> > Thanks all the same,
> >
> > Regards,
> >
> > Saimon
> >
> >
> > --------------------------
> > Saimon Moore
> > Departamento TI
> > CondisLine e-Commerce S.A.
> >
> > telf./fax: 93 565 3400 ext. 473 / 935752325 
> http://www.condisline.com
> > 
> mailto://simon_moore-HnN13UdsTkzz1n+OaKNE4w@public.gmane.org
> 
> -- 
> [In Linux We Trust]
> Galin Yordanov
> galin-Dn6zUBO643CDvotElmWtJA@public.gmane.org
> 


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Re: Speedstep-centrino problems

[Rich Townsend]

I was under the impression that this patch was possibly dangerous. This 
is because the Pentium M Dothan series (the recent-ish ones, with 2Mb 
cache) each come in four variants, VID#A through VID#D. Each variant has 
a different set of voltage characteristics, but unforutnately there is 
no way to tell which variant one has installed (is this actually true? 
How about a visual inspection?)

The patch assumes that your Pentium M is a VID#C variant. If this is not 
the case, and there is too much of a mismatch between the voltage 
characteristics, then (possibly-serious) problems may ensue.

This is my understanding as to why Dothan frequency tables have not yet 
appeared in any "official" patch, and to why this particular patch was 
rejected.

cheers,

Rich

Galin Yordanov wrote:
> Hello,
> 
> I have Acer TM4500 with Centrino 1.6 (Dothan)and i had the same problem ..
> then i found this patch (attached), cannot remember where i found it but it 
> works ;)
> 
> Regards,
> Galin
> On Thursday 10 February 2005 04:38 am, Simon Moore wrote:
> 
>>Hi,
>>
>>I'm trying to get acpi cpu throttling working for my Dell Inspiron 510m
>>with a Pentium M Centrino 1.6 Ghz cpu.
>>
>>I have tried a number of possibilites but have not got anywhere. I have
>>an open case over at the gentoo forums but we have not had success in
>>resolving this problem.
>>
>>This is my last ditch attempt to try and find a solution to this
>>problem. I think I have exhausted most possible avenues so I'm trying to
>>get some kernel hacker on board and help me with this.
>>
>>I would very much appreciate it if someone could take a look at this
>>thread and possbily come up with a suggestion of what might be causing
>>this. (http://forums.gentoo.org/viewtopic.php?p=2076710) I have a lot of
>>info in that thread that you should find useful but if there's any other
>>info you require I'll post it tonight.
>>
>>For what it's worth I hope it intrigues some of you enough to help me
>>out.
>>
>>Thanks all the same,
>>
>>Regards,
>>
>>Saimon
>>
>>
>>--------------------------
>>Saimon Moore
>>Departamento TI
>>CondisLine e-Commerce S.A.
>>
>>telf./fax: 93 565 3400 ext. 473 / 935752325
>>http://www.condisline.com
>>mailto://simon_moore-HnN13UdsTkzz1n+OaKNE4w@public.gmane.org
> 
> 



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RE: Speedstep-centrino problems

[Simon Moore]

Thanks for warning me about that.

I suppose I could ask Dell which variant they installed (or how to find
out which variant is installed). If I were to be certain which variant
it was, would the patch be safe if modified accordingly?

Or anyone up to patching it such that the variant can be defined at
runtime? ;) I would but I'm just a stupid java developer. :)

Reagrds,

Saimon

> -----Mensaje original-----
> De: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org 
> [mailto:acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org] En nombre de 
> Rich Townsend
> Enviado el: jueves, 10 de febrero de 2005 13:06
> Para: galin-Dn6zUBO643CDvotElmWtJA@public.gmane.org
> CC: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> Asunto: Re: [ACPI] Speedstep-centrino problems
> 
> 
> I was under the impression that this patch was possibly 
> dangerous. This 
> is because the Pentium M Dothan series (the recent-ish ones, with 2Mb 
> cache) each come in four variants, VID#A through VID#D. Each 
> variant has 
> a different set of voltage characteristics, but unforutnately 
> there is 
> no way to tell which variant one has installed (is this 
> actually true? 
> How about a visual inspection?)
> 
> The patch assumes that your Pentium M is a VID#C variant. If 
> this is not 
> the case, and there is too much of a mismatch between the voltage 
> characteristics, then (possibly-serious) problems may ensue.
> 
> This is my understanding as to why Dothan frequency tables 
> have not yet 
> appeared in any "official" patch, and to why this particular 
> patch was 
> rejected.
> 
> cheers,
> 
> Rich
> 
> Galin Yordanov wrote:
> > Hello,
> > 
> > I have Acer TM4500 with Centrino 1.6 (Dothan)and i had the same 
> > problem .. then i found this patch (attached), cannot 
> remember where i 
> > found it but it works ;)
> > 
> > Regards,
> > Galin
> > On Thursday 10 February 2005 04:38 am, Simon Moore wrote:
> > 
> >>Hi,
> >>
> >>I'm trying to get acpi cpu throttling working for my Dell Inspiron 
> >>510m with a Pentium M Centrino 1.6 Ghz cpu.
> >>
> >>I have tried a number of possibilites but have not got anywhere. I 
> >>have an open case over at the gentoo forums but we have not had 
> >>success in resolving this problem.
> >>
> >>This is my last ditch attempt to try and find a solution to this 
> >>problem. I think I have exhausted most possible avenues so 
> I'm trying 
> >>to get some kernel hacker on board and help me with this.
> >>
> >>I would very much appreciate it if someone could take a 
> look at this 
> >>thread and possbily come up with a suggestion of what might 
> be causing 
> >>this. (http://forums.gentoo.org/viewtopic.php?p=2076710) I 
> have a lot 
> >>of info in that thread that you should find useful but if 
> there's any 
> >>other info you require I'll post it tonight.
> >>
> >>For what it's worth I hope it intrigues some of you enough 
> to help me 
> >>out.
> >>
> >>Thanks all the same,
> >>
> >>Regards,
> >>
> >>Saimon
> >>
> >>
> >>--------------------------
> >>Saimon Moore
> >>Departamento TI
> >>CondisLine e-Commerce S.A.
> >>
> >>telf./fax: 93 565 3400 ext. 473 / 935752325 
> http://www.condisline.com
> >>mailto://simon_moore-HnN13UdsTkzz1n+OaKNE4w@public.gmane.org
> > 
> > 
> 
> 
> 
> -------------------------------------------------------
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> _______________________________________________
> 
> Acpi-devel mailing list
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> 


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Re: Speedstep-centrino problems

[Rich Townsend]

Simon Moore wrote:
> Thanks for warning me about that.
> 
> I suppose I could ask Dell which variant they installed (or how to find
> out which variant is installed). If I were to be certain which variant
> it was, would the patch be safe if modified accordingly?

I would think the chances are exceedingly small of you a) finding 
someone at Dell who actually knows this, and b) getting the information 
out of them.

> 
> Or anyone up to patching it such that the variant can be defined at
> runtime? ;) I would but I'm just a stupid java developer. :)

The problem is not so much to do with the ability to choose the 
appropriate VID#, it is more about working out *which* VID# to choose. 
If someone could address the latter question, I'd be more than happy to 
have a shot at the former.

cheers,

Rich


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RE: Speedstep-centrino problems

[Simon Moore]

Ok, I'll try and find out how to identify which VID# to choose. Either
through dell or intel.

If I do, try and give it a go,

Thanks.

Btw I can't seem to find the Dothan datasheet that was specified
(www.intel.com/design/mobile/datashts/30218903.pdf) but I found this one
(http://www.intel.com/design/mobile/datashts/302189.htm -->
ftp://download.intel.com/design/mobile/datashts/30218905.pdf) which now
specifies 6 VID# variants ;)



> -----Mensaje original-----
> De: Rich Townsend [mailto:rhdt-OBnUx95tOyn10jlvfTC4gA@public.gmane.org] 
> Enviado el: jueves, 10 de febrero de 2005 14:08
> Para: Simon Moore; acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> Asunto: Re: [ACPI] Speedstep-centrino problems
> 
> 
> Simon Moore wrote:
> > Thanks for warning me about that.
> > 
> > I suppose I could ask Dell which variant they installed (or how to 
> > find out which variant is installed). If I were to be certain which 
> > variant it was, would the patch be safe if modified accordingly?
> 
> I would think the chances are exceedingly small of you a) finding 
> someone at Dell who actually knows this, and b) getting the 
> information 
> out of them.
> 
> > 
> > Or anyone up to patching it such that the variant can be defined at 
> > runtime? ;) I would but I'm just a stupid java developer. :)
> 
> The problem is not so much to do with the ability to choose the 
> appropriate VID#, it is more about working out *which* VID# 
> to choose. 
> If someone could address the latter question, I'd be more 
> than happy to 
> have a shot at the former.
> 
> cheers,
> 
> Rich
> 


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Re: Speedstep-centrino problems

[Dominik Brodowski]

> The problem is not so much to do with the ability to choose the 
> appropriate VID#, it is more about working out *which* VID# to choose. 
> If someone could address the latter question, I'd be more than happy to 
> have a shot at the former.

At some frequency levels, you can read out the current settings and
determine which VID# is used. At other frequency levels, you cannot,
though, as some VID# can have the same voltage for certain levels.
Therefore, I do not see a runtime-way to determine the correct VID# to
choose.

	Dominik


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Re: Speedstep-centrino problems

[Bruno Ducrot]

On Thu, Feb 10, 2005 at 10:38:31AM +0100, Simon Moore wrote:
> Hi,
> 
> I'm trying to get acpi cpu throttling working for my Dell Inspiron 510m
> with a Pentium M Centrino 1.6 Ghz cpu.
> 

I need the full acpi dump (not just dsdt) to debug this.

wget ftp://ftp.kernel.org//pub/linux/kernel/people/lenb/acpi/utils/pmtools-20031210.tar.bz2
tar xjvfp pmtools-20031210.tar.bz2
cd pmtools-20031210/acpidmp
make
sudo ./acpidmp > acpidmp.out
bzip2 acpidmp.out 

Then mail me (privately) the acpidmp.out.bz2

Cheers,

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.


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Re: Speedstep-centrino problems

[Johan Vromans]

Rich Townsend <rhdt-OBnUx95tOyn10jlvfTC4gA@public.gmane.org> writes:

> Each
> variant has a different set of voltage characteristics, but
> unforutnately there is no way to tell which variant one has installed
> (is this actually true? How about a visual inspection?)

Dominik once gave a program called msr_is32_perf_status that reveals the
current CPU speed and voltage. I used it to find the 'real' speeds my
CPU ran (the DSDT contained wrong values).
Would that program be helpful here?

-- Johan


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Dothan VID# identification script (was Re: Speedstep-centrino problems)

[Rich Townsend]

[-- Attachment #1: Type: text/plain, Size: 3265 bytes --]

Dominik Brodowski wrote:
>>The problem is not so much to do with the ability to choose the 
>>appropriate VID#, it is more about working out *which* VID# to choose. 
>>If someone could address the latter question, I'd be more than happy to 
>>have a shot at the former.
> 
> 
> At some frequency levels, you can read out the current settings and
> determine which VID# is used. At other frequency levels, you cannot,
> though, as some VID# can have the same voltage for certain levels.
> Therefore, I do not see a runtime-way to determine the correct VID# to
> choose.
> 
> 	Dominik

The attached Perl script demonstrates one run-time approach to 
determining the correct VID# to use. In principle, this approach could 
be integrated into the kernel, to allow Pentium M Dothan support to be 
added to speedstep-centrino.

Rather paradoxically, for this script to work, cpufreq must already be 
up and running. This is because the script uses the entries in 
/sys/devices/.../cpufreq to get a *provisional* list of processor 
frequencies. It is expected that this list be obtained from the 
processor P-state information in the DSDT, so for the script to work, 
make sure you have the acpi_cpufreq table helper installed (see 
instructions at the end of this post).

The script iterates through the provisional frequency list, setting the 
processor frequency using the scaling_[max|min]_freq files in 
/sys/devices/.../cpufreq. The frequency and voltage are then read back 
using the IA32_PERF_STATUS MSR. This way, a frequency/voltage table is 
built up for the system. Each entry of the table is *guaranteed* to be a 
valid frequency/voltage pair, although some frequencies may be missing 
from the table due to DSDT bugs (on my 1.6Ghz Dothan system, the DSDT 
mislabels the 1000 MHz frequency, and omits the 800 Mhz frequency).

The frequency/voltage table is then cross-checked against *all* of the 
Pentium M Dothan tables published by Intel (i.e., all of the possible 
processor and VID# combinations). If there is a single, *unique* match, 
then the Perl script prints out this match, plus the *full* 
frequency/voltage table (including entries that the DSDT may have 
missed). Example output on my system is as follows:

Identified Intel(r) Pentum(r) M Processor 725 Core, 1.6 Ghz, VID#A
Frequency/voltage table:
  600 MHz        ->      988 mV
  800 MHz        ->      1068 mV
  1000 MHz       ->      1132 mV
  1200 MHz       ->      1212 mV
  1400 MHz       ->      1276 mV
  1600 MHz       ->      1340 mV

Of course, we can't guarantee that there will always be a match; or that 
there won't be duplicate matches. Also, this approach relies on having 
ACPI P-states, to build up the frequency/voltage table. However, it 
still seems to me to be a pretty robust way of determining the VID# in a 
system, and one that could be incorporated into speedstep-centrino. 
Dominik, what do you think?

cheers

Rich

PS Almost forgot: for those wanting to use the script, make sure you 
have cpufreq enabled in your kernel, and make sure the ACPI Processor 
P-states driver is installed (CONFIG_X86_ACPI_CPUFREQ), and that you 
also have the userspace governor installed 
(CONFIG_CPU_FREQ_GOV_USERSPACE). Then, just run the script *as root*, 
with no arguments.

[-- Attachment #2: dothan_id.pl --]
[-- Type: text/plain, Size: 5703 bytes --]

#!/usr/bin/perl -w
#
#  dothan_id.pl
#
#  (c) 2005 Rich Townsend <rhdt-OBnUx95tOyn10jlvfTC4gA@public.gmane.org>
#
# Script to identify the voltage ID (VID#) of a 
# Pentium M Dothan CPU

# Constants

$CPUFREQ_DIR = "/sys/devices/system/cpu/cpu0/cpufreq";

$MSR_FILE = "/dev/cpu/0/msr";
$MSR_IA32_PERF_STATUS = 0x198;

$DEBUG = 0;

# Enumerate the avaliable frequencies

@afreqs = split(' ', cpufreq_read('scaling_available_frequencies'));

# Set the governor to userspace

cpufreq_write('scaling_governor', 'userspace');
cpufreq_read('scaling_governor') eq 'userspace' or die "Unable to set governor to userspace\n";

# Iterate through the available frequencies, building
# up the frequency/voltage table

%freq_table = ();

foreach my $afreq (sort { $a <=> $b } @afreqs) {

# Set the current frequency

    cpufreq_write('scaling_max_freq', $afreq);
    cpufreq_write('scaling_min_freq', $afreq);

    cpufreq_read('scaling_cur_freq') == $afreq or die "Unable to set frequency to $afreq\n";

# Read back the frequency and voltage into using
# the MSR

    my $msr_str;

    open MSR_FILE, "<$MSR_FILE" or die "Unable to read from $MSR_FILE\n$!";
    seek MSR_FILE, $MSR_IA32_PERF_STATUS, 0;
    read MSR_FILE, $msr_str, 8;
    close MSR_FILE;

    my $msr_val = 0;
    
    for(my $i = 0; $i < 8; $i++) {
	$msr_val <<= 8;
	$msr_val += ord(substr($msr_str, 7-$i, 1));
    }

    $msr_val &= 0xffffffff;

    my $freq = 100*($msr_val>>8 & 0xff);
    my $volt = 16*($msr_val & 0xff) + 700;

    $freq_table{$freq} = $volt;

    $DEBUG && printf("Available frequency %d gives frequency %d MHz @ %d mV\n", $afreq, $freq, $volt);
}

# Set up the voltage data table, taken from Intel's 
# January 2005 datasheet for the Pentium M Dothan

%DOTHAN_DATA = (
		715 => {
		    'rating' => '1.5',
		    'freqs' => [600, 800, 1000, 1200, 1500],
		    'VIDs' => {
			'A' => [988, 1068, 1148, 1228, 1340],
			'B' => [988, 1068, 1148, 1212, 1324],
			'C' => [988, 1068, 1132, 1212, 1308],
			'D' => [988, 1052, 1116, 1180, 1276]
			}
		},
		725 => {
		    'rating' => '1.6',
		    'freqs' => [600, 800, 1000, 1200, 1400, 1600],
		    'VIDs' => {
			'A' => [988, 1068, 1132, 1212, 1276, 1340],
			'B' => [988, 1068, 1132, 1196, 1260, 1324],
			'C' => [988, 1052, 1116, 1180, 1244, 1308],
			'D' => [988, 1052, 1116, 1164, 1228, 1276]
			}
		},
		735 => {
		    'rating' => '1.7',
		    'freqs' => [600, 800, 1000, 1200, 1400, 1700],
		    'VIDs' => {
			'A' => [988, 1052, 1116, 1180, 1244, 1340],
			'B' => [988, 1052, 1116, 1180, 1244, 1324],
			'C' => [988, 1052, 1116, 1164, 1228, 1308],
			'D' => [988, 1052, 1100, 1148, 1212, 1276]
			}
		},
		745 => {
		    'rating' => '1.8',
		    'freqs' => [600, 800, 1000, 1200, 1400, 1600, 1800],
		    'VIDs' => {
			'A' => [988, 1052, 1116, 1164, 1228, 1292, 1340],
			'B' => [988, 1052, 1100, 1164, 1212, 1276, 1324],
			'C' => [988, 1052, 1100, 1148, 1212, 1260, 1308],
			'D' => [988, 1036, 1084, 1132, 1180, 1228, 1276]
			}
		},
		755 => {
		    'rating' => '2.0',
		    'freqs' => [600, 800, 1000, 1200, 1400, 1600, 1800, 2000],
		    'VIDs' => {
			'A' => [988, 1052, 1100, 1148, 1196, 1244, 1292, 1340],
			'B' => [988, 1036, 1084, 1132, 1180, 1228, 1276, 1324],
			'C' => [988, 1036, 1084, 1132, 1180, 1228, 1276, 1308],
			'D' => [988, 1036, 1084, 1116, 1164, 1196, 1244, 1276]
			}
		},
		765 => {
		    'rating' => '2.1',
		    'freq' => [600, 800, 1000, 1200, 1400, 1600, 1800, 2100],
		    'VIDs' => {
			'A' => [988, 1036, 1084, 1132, 1180, 1228, 1276, 1340],
			'B' => [988, 1036, 1084, 1132, 1180, 1212, 1260, 1324],
			'C' => [988, 1036, 1084, 1116, 1164, 1212, 1244, 1308],
			'E' => [988, 1052, 1100, 1148, 1196, 1244, 1292, 1356]
			}
		}
		);

# Attempt to match the frequency table against one
# of the Dothan tables

@match_cpus = ();
@match_VIDs = ();

foreach $cpu (keys %DOTHAN_DATA) {

    foreach $VID (keys %{$DOTHAN_DATA{$cpu}->{'VIDs'}}) {

# Dynamically create a table for the current cpu/VID
# pair

	my %dothan_freq_table = ();

	for(my $i_freq = 0; $i_freq <= $#{$DOTHAN_DATA{$cpu}->{'freqs'}}; $i_freq++) {
	    my $freq = $DOTHAN_DATA{$cpu}->{'freqs'}->[$i_freq];
	    my $volt = $DOTHAN_DATA{$cpu}->{'VIDs'}->{$VID}->[$i_freq];
	    $dothan_freq_table{$freq} = $volt;
	}
			 
# See whether the frequency table is a 
# subset of the Dothan table

	my $match = 1;

	foreach my $freq (keys %freq_table) {
	    if(!exists($dothan_freq_table{$freq}) ||
	       $dothan_freq_table{$freq} != $freq_table{$freq}) {
		$match = 0;
		last;
	    }
	}
	    
# If a match was found, store the cpu and VID

	if($match) {
	    push @match_cpus, $cpu;
	    push @match_VIDs, $VID;
	}
	
    }
}	
	
# Print out the results

if(@match_cpus == 0) {

    print "No matches found\n";

}
elsif(@match_cpus == 1) {

    my $cpu = $match_cpus[0];
    my $VID = $match_VIDs[0];

    printf("Identified Intel(r) Pentum(r) M Processor %d Core, %2.1f Ghz, VID#%s\n", 
	   $cpu, $DOTHAN_DATA{$cpu}->{'rating'}, $VID);

    printf("Frequency/voltage table:\n");

    for(my $i_freq = 0; $i_freq <= $#{$DOTHAN_DATA{$cpu}->{'freqs'}}; $i_freq++) {
	my $freq = $DOTHAN_DATA{$cpu}->{'freqs'}->[$i_freq];
	my $volt = $DOTHAN_DATA{$cpu}->{'VIDs'}->{$VID}->[$i_freq];
	printf(" %d MHz\t->\t%d mV\n", $freq, $volt);
    }

}
else {

    print "Duplicate matches found, no identification possible\n";

}

# Finish

sub cpufreq_read {

    open CPUFREQ, "<$CPUFREQ_DIR/$_[0]" or die "Unable to read from $CPUFREQ_DIR/$_[0]\n$!";
    my $line = <CPUFREQ>;
    close CPUFREQ;

    chomp $line;

    return $line;

}

sub cpufreq_write {

    open CPUFREQ, ">$CPUFREQ_DIR/$_[0]" or die "Unable to write to $CPUFREQ_DIR/$_[0]\n$!";
    print CPUFREQ $_[1];
    close CPUFREQ;

}