STPGNT with athlonXP PowerNow

STPGNT with athlonXP PowerNow

[Toula Michael]

Hi,
I've just read an interesting HOWTO called Athlon-Powersaving-HOWTO 
(http://www.daniel.nofftz.net/linux/Athlon-Powersaving-HOWTO.html) 
...and also a more theoretical article here 
http://vcool.occludo.net/VC_Theory.html
And I was wondering if setting the “Disconnect eable when STPGNT 
detected” bit in the north bridge of the chipset is useful with an 
Athlon-XP power now (the mobile version)
Maybe this the bit is already set or not available ? It may not have any 
effect…
Any idea ?

Thx a lot

Re: STPGNT with athlonXP PowerNow

[Ducrot Bruno]

On Wed, Sep 03, 2003 at 03:59:41PM +0200, Toula Michael wrote:
> Hi,
> I've just read an interesting HOWTO called Athlon-Powersaving-HOWTO 
> (http://www.daniel.nofftz.net/linux/Athlon-Powersaving-HOWTO.html) 
> ...and also a more theoretical article here 
> http://vcool.occludo.net/VC_Theory.html
> And I was wondering if setting the ?Disconnect eable when STPGNT 
> detected? bit in the north bridge of the chipset is useful with an 
> Athlon-XP power now (the mobile version)
> Maybe this the bit is already set or not available ? It may not have any 
> effect?

It is usefull, but not for powernow stuff.  AFAIK you need at least
acpi and check that you have something like that:

ducrot@poupon:~$ cat /proc/acpi/processor/CPU0/power 
active state:            C2
default state:           C1
bus master activity:     00000000
states:
    C1:                  promotion[C2] demotion[--] latency[000] usage[00001220]
   *C2:                  promotion[--] demotion[C1] latency[090] usage[00006826]
    C3:                  <not supported>

If you dont have C2 then you may have to complain to the manufacturer, and
hack a little the DSDT.
If you don't see any kind of more power saving (fan always on, shutdown due
to overheat situation, etc.) then complain to acpi developpers, and use the
Athlon-Powersaving-HOWTO in the mean time in order to set the bit you
mention.

Cheers,

-- 
Ducrot Bruno

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

Re: STPGNT with athlonXP PowerNow

[Toula Michael]

Ducrot Bruno wrote:

>On Wed, Sep 03, 2003 at 03:59:41PM +0200, Toula Michael wrote:
>  
>
>>Hi,
>>I've just read an interesting HOWTO called Athlon-Powersaving-HOWTO 
>>(http://www.daniel.nofftz.net/linux/Athlon-Powersaving-HOWTO.html) 
>>...and also a more theoretical article here 
>>http://vcool.occludo.net/VC_Theory.html
>>And I was wondering if setting the ?Disconnect eable when STPGNT 
>>detected? bit in the north bridge of the chipset is useful with an 
>>Athlon-XP power now (the mobile version)
>>Maybe this the bit is already set or not available ? It may not have any 
>>effect?
>>    
>>
>
>It is usefull, but not for powernow stuff.  AFAIK you need at least
>acpi and check that you have something like that:
>
>ducrot@poupon:~$ cat /proc/acpi/processor/CPU0/power 
>active state:            C2
>default state:           C1
>bus master activity:     00000000
>states:
>    C1:                  promotion[C2] demotion[--] latency[000] usage[00001220]
>   *C2:                  promotion[--] demotion[C1] latency[090] usage[00006826]
>    C3:                  <not supported>
>
>If you dont have C2 then you may have to complain to the manufacturer, and
>hack a little the DSDT.
>
C2 state works fine for me

>If you don't see any kind of more power saving (fan always on, shutdown due
>to overheat situation, etc.) then complain to acpi developpers,
>
Acpi works fine, lucky ACPI developpers ;)

> and use the
>Athlon-Powersaving-HOWTO in the mean time in order to set the bit you
>mention.
>
Ok so this trick is not useful for freqency scalling (cpufreq does), but 
I can save power when my processor is idle ?

>
>Cheers,
>
THX again,

>
>  
>

Re: STPGNT with athlonXP PowerNow

[Zhijian Lu]

Hi,
I have a question related to this topic:
Whether the mobile athlonXP will disconnect the bus 
connection in response to the HLT instruction even ACPI is 
not installed? Because we observed that the idle power is 
almost the same no matter what voltage/frequency 
combination is used(if PLL doesn't stop, the power 
consumption should be affectecd by the running frequency 
and voltage)?

Thanks,
Zhijian

Re: STPGNT with athlonXP PowerNow

[Ducrot Bruno]

On Wed, Sep 03, 2003 at 12:41:08PM -0400, Zhijian Lu wrote:
> Hi,
> I have a question related to this topic:
> Whether the mobile athlonXP will disconnect the bus 
> connection in response to the HLT instruction even ACPI is 
> not installed? Because we observed that the idle power is 
> almost the same no matter what voltage/frequency 
> combination is used(if PLL doesn't stop, the power 
> consumption should be affectecd by the running frequency 
> and voltage)?
> 

In short, I don't know.  HLT does nothing for my laptop
(based upon a Athlon XP-M 2200).  It seems to be possible
to do so (there is some ref. to a MSR called 'CLK_Ctl' but
unfortunately doc for it is available only via NDA apparently).

But since that work via acpi stuff
(replace the 'hlt' by a io read to LVL2 register of the
southbridge) I must admit that I have not searched so hard.

-- 
Ducrot Bruno

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