em64t speedstep technology not supported in kernel yet?

em64t speedstep technology not supported in kernel yet?

[Richard Wohlstadter]

Hello all,

We recently had Intel give our company a roadmap presentation where they 
told us that their enhanced speedstep technology was supported by linux 
kernels 2.6.9+.  I have since tried to get cpufreq speedstep driver to 
work with no luck on our em64t Xeon 3.6g processors.  Intel even has a 
webpage describing the technology and how to get it working at url: 
http://www.intel.com/cd/ids/developer/asmo-na/eng/195910.htm?prn=Y

I made a bugzilla report to redhat [Bug 169290] and got a reply that 
none of the Xeon's were supported yet on speedstep because they cannot 
find documentation detailing the tables of frequencies these CPUs support.

The only processor I have had luck with so far is a 32-bit Xeon with the 
p4-clockmod driver(which does not appear to be present in the x86-64 
kernel).

Anyone have any knowledge regarding cpufreq and when the em64t's are 
going have a linux driver supporting the speedstep technology?  If it is 
an issue of Intel not providing the neccessary info, maybe I can press 
the issue with the gentlemen that came to my office and stated support 
was there already.

Thanks for any info and advice.  Please CC my on any replies since I am 
not on the list.

Rich Wohlstadter
Genome Sequencing Center
Washington Univ. of St. Louis

Re: em64t speedstep technology not supported in kernel yet?

[Wes Felter]

Richard Wohlstadter wrote:
> Hello all,
> 
> We recently had Intel give our company a roadmap presentation where they 
> told us that their enhanced speedstep technology was supported by linux 
> kernels 2.6.9+.  I have since tried to get cpufreq speedstep driver to 
> work with no luck on our em64t Xeon 3.6g processors.  Intel even has a 
> webpage describing the technology and how to get it working at url: 
> http://www.intel.com/cd/ids/developer/asmo-na/eng/195910.htm?prn=Y

I think this is a BIOS problem; the BIOS needs to provide the proper 
ACPI frequency/voltage tables for cpufreq to use. You might want to 
harass your system/motherboard vendor.

Alternately maybe you can find someone who can give you the secret table 
and then you can just hardcode it into the driver.

> The only processor I have had luck with so far is a 32-bit Xeon with the 
> p4-clockmod driver(which does not appear to be present in the x86-64 
> kernel).

Beware that p4-clockmod won't increase the power efficiency of your 
system. (As an aside, clock modulation is so simple that you can do it 
from userspace in a few lines of C if you modprobe msr. This works on 
x86-64.)

Wes Felter - wesley@felter.org

RE: Re: em64t speedstep technology not supported in kernel yet?

[Pallipadi, Venkatesh]

>-----Original Message-----
>From: linux-kernel-owner@vger.kernel.org 
>[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Wes Felter
>Sent: Thursday, September 29, 2005 11:58 AM
>To: linux-kernel@vger.kernel.org
>Subject: Re: em64t speedstep technology not supported in kernel yet?
>
>Richard Wohlstadter wrote:
>> Hello all,
>> 
>> We recently had Intel give our company a roadmap 
>presentation where they 
>> told us that their enhanced speedstep technology was 
>supported by linux 
>> kernels 2.6.9+.  I have since tried to get cpufreq speedstep 
>driver to 
>> work with no luck on our em64t Xeon 3.6g processors.  Intel 
>even has a 
>> webpage describing the technology and how to get it working at url: 
>> http://www.intel.com/cd/ids/developer/asmo-na/eng/195910.htm?prn=Y
>
>I think this is a BIOS problem; the BIOS needs to provide the proper 
>ACPI frequency/voltage tables for cpufreq to use. You might want to 
>harass your system/motherboard vendor.
>
>Alternately maybe you can find someone who can give you the 
>secret table 
>and then you can just hardcode it into the driver.
>

Yes. Make sure speedstep is  supported and enabled in BIOS. Typically,
there will be a BIOS config option under CPU section, called Speedstep, 
Enhanced Speedstep or EIST or something like that. 

Which kernels did you try? Also, if you can send the acpidump output 
from pmtools here 
http://www.kernel.org/pub/linux/kernel/people/lenb/acpi/utils/
We can see whether BIOS is indeed supporting speedstep or not.

Thanks,
Venki

Re: em64t speedstep technology not supported in kernel yet?

[Dave Jones]

On Fri, Sep 30, 2005 at 05:20:03AM -0700, Pallipadi, Venkatesh wrote:
 > 
 > >-----Original Message-----
 > >From: linux-kernel-owner@vger.kernel.org 
 > >[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Wes Felter
 > >Sent: Thursday, September 29, 2005 11:58 AM
 > >To: linux-kernel@vger.kernel.org
 > >Subject: Re: em64t speedstep technology not supported in kernel yet?
 > >
 > >Richard Wohlstadter wrote:
 > >> Hello all,
 > >> 
 > >> We recently had Intel give our company a roadmap 
 > >presentation where they 
 > >> told us that their enhanced speedstep technology was 
 > >supported by linux 
 > >> kernels 2.6.9+.  I have since tried to get cpufreq speedstep 
 > >driver to 
 > >> work with no luck on our em64t Xeon 3.6g processors.  Intel 
 > >even has a 
 > >> webpage describing the technology and how to get it working at url: 
 > >> http://www.intel.com/cd/ids/developer/asmo-na/eng/195910.htm?prn=Y
 > >
 > >I think this is a BIOS problem; the BIOS needs to provide the proper 
 > >ACPI frequency/voltage tables for cpufreq to use. You might want to 
 > >harass your system/motherboard vendor.
 > >
 > >Alternately maybe you can find someone who can give you the 
 > >secret table and then you can just hardcode it into the driver.
 > 
 > Yes. Make sure speedstep is  supported and enabled in BIOS. Typically,
 > there will be a BIOS config option under CPU section, called Speedstep, 
 > Enhanced Speedstep or EIST or something like that. 

The BIOS tables make no difference at all however to the speedstep-centrino
module  (which in retrospect really should have been speedstep-est or something)
as it has no OP() tables or cpu recognition for Xeons.

		Dave

RE: em64t speedstep technology not supported in kernel yet?

[Pallipadi, Venkatesh]

>-----Original Message-----
>From: Dave Jones [mailto:davej@redhat.com] 
>Sent: Friday, September 30, 2005 6:05 AM
>To: Pallipadi, Venkatesh
>Cc: Wes Felter; linux-kernel@vger.kernel.org
>Subject: Re: em64t speedstep technology not supported in kernel yet?
>
>On Fri, Sep 30, 2005 at 05:20:03AM -0700, Pallipadi, Venkatesh wrote:
> > 
> > >-----Original Message-----
> > >From: linux-kernel-owner@vger.kernel.org 
> > >[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Wes Felter
> > >Sent: Thursday, September 29, 2005 11:58 AM
> > >To: linux-kernel@vger.kernel.org
> > >Subject: Re: em64t speedstep technology not supported in 
>kernel yet?
> > >
> > >Richard Wohlstadter wrote:
> > >> Hello all,
> > >> 
> > >> We recently had Intel give our company a roadmap 
> > >presentation where they 
> > >> told us that their enhanced speedstep technology was 
> > >supported by linux 
> > >> kernels 2.6.9+.  I have since tried to get cpufreq speedstep 
> > >driver to 
> > >> work with no luck on our em64t Xeon 3.6g processors.  Intel 
> > >even has a 
> > >> webpage describing the technology and how to get it 
>working at url: 
> > >> 
>http://www.intel.com/cd/ids/developer/asmo-na/eng/195910.htm?prn=Y
> > >
> > >I think this is a BIOS problem; the BIOS needs to provide 
>the proper 
> > >ACPI frequency/voltage tables for cpufreq to use. You 
>might want to 
> > >harass your system/motherboard vendor.
> > >
> > >Alternately maybe you can find someone who can give you the 
> > >secret table and then you can just hardcode it into the driver.
> > 
> > Yes. Make sure speedstep is  supported and enabled in BIOS. 
>Typically,
> > there will be a BIOS config option under CPU section, 
>called Speedstep, 
> > Enhanced Speedstep or EIST or something like that. 
>
>The BIOS tables make no difference at all however to the 
>speedstep-centrino
>module  (which in retrospect really should have been 
>speedstep-est or something)
>as it has no OP() tables or cpu recognition for Xeons.
>
>		Dave

Actually, speedstep-centrino works in two modes. One OP() 
table based mode and the other ACPI table based mode. So, 
BIOS ACPI tables do matter for the second mode and things 
work without a static OP table.

Also, OP() table based modes is not really scalable as one 
has to enter new tabled for every new model and also not 
complete as it cannot take ACPI events (say different 
P-states for battery or AC on laptop, which may not matter 
that much for Xeon...). That's the reason we want to have 
ACPI/BIOS based speedstep as much as possible. Of course 
there will always be broken BIOSes which we have 
to workaround....

In this particular case though, for Xeon with Enhanced Speedstep, 
acpi-cpufreq should be the driver of choice as there is a need 
for coordination of HT siblings, which happen in BIOS at the 
moment with most BIOSes. That is the reason, I want to make 
sure BIOS supports Enhanced Speedstep in this case.

Thanks,
Venki

Re: em64t speedstep technology not supported in kernel yet?

[Dave Jones]

On Fri, Sep 30, 2005 at 06:20:15AM -0700, Pallipadi, Venkatesh wrote:

 > Actually, speedstep-centrino works in two modes. One OP() 
 > table based mode and the other ACPI table based mode. So, 
 > BIOS ACPI tables do matter for the second mode and things 
 > work without a static OP table.

True. Ack, I've spent too much time playing with that driver
and broken BIOS's lately, that I'd forgotten about this. :)

 > In this particular case though, for Xeon with Enhanced Speedstep, 
 > acpi-cpufreq should be the driver of choice as there is a need 
 > for coordination of HT siblings, which happen in BIOS at the 
 > moment with most BIOSes. That is the reason, I want to make 
 > sure BIOS supports Enhanced Speedstep in this case.

Ok, that makes sense.

		Dave