From: Robert Hancock <hancockr@shaw.ca>
To: Joe Harvell <jharvell@dogpad.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: ACPI C and P states on Conroe
Date: Tue, 30 Jan 2007 17:09:25 -0600 [thread overview]
Message-ID: <45BFD025.10902@shaw.ca> (raw)
In-Reply-To: <fa.kcyyw0/u0jusCdUVaHf0ecFyj0E@ifi.uio.no>
Joe Harvell wrote:
> I am trying to enable all the power saving features I can on my Conroe
> E6600. After much searching on the web, I am a little confused about
> the Linux kernel support for ACPI on the Conroe.
>
> Here is my setup:
> Intel Core2 Duo E6600
> Asus P5-B Deluxe board (Intel P965).
> I am running a Gentoo kernel based on 2.6.19.4.
>
> I have managed to enable EIST using cpufreq with the speedstep-centrino
> driver. But my understanding from browsing the ACPI spec is that this
> is still within C0, i.e. not much power savings.
C-states are something else entirely, frequency scaling and C-states are
essentially independent. You can be in lower frequency and C1, C2, etc.
and it will still use less power.
>
> Here are my questions:
>
> 1) For P states, which cpufreq driver should I be using? I've heard
> speedstep-centrino is deprecated (but only some aspects of it) that are
Right.
> being moved into acpi-cpufreq. But I can't get acpi-cpufreq to load in
> my kernel version. Also, I would have thought speedstep-ich would be
Are you sure? Are you getting error messages?
> the driver, just based on the name. How do I know (other than trying
No, that's only for some older chipsets.
> all modules to see which one loads) which one I should be using?
That's the easiest way, and that's what Fedora does for example (just
compile all the drivers into the kernel). acpi-cpufreq should be the one
for all modern boards, however.
> 2) What kind of support for C1-C3 does the Conroe have? The ACPI spec
> says C2 and C3 require chipset support on the motherboard. Does P965
> have that. Does it matter between boards (e.g. P5B)?
The kernel will only use C2 and C3 if the motherboard exports support
for it through ACPI. Most desktop boards don't, this is normally only
found on laptops.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/
next parent reply other threads:[~2007-01-30 23:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <fa.kcyyw0/u0jusCdUVaHf0ecFyj0E@ifi.uio.no>
2007-01-30 23:09 ` Robert Hancock [this message]
2007-01-31 0:18 ` ACPI C and P states on Conroe Joe Harvell
2007-01-30 17:35 Joe Harvell
2007-01-31 1:17 ` Len Brown
-- strict thread matches above, loose matches on Subject: below --
2007-01-30 17:33 Joe Harvell
2007-01-30 22:31 ` Pallipadi, Venkatesh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=45BFD025.10902@shaw.ca \
--to=hancockr@shaw.ca \
--cc=jharvell@dogpad.net \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox