From: Robert Hancock <hancockrwd@gmail.com>
To: Mahmood Naderan <mahmood.nt@gmail.com>
Cc: linux-acpi@vger.kernel.org
Subject: Re: BIOS and CPU C_states are strange
Date: Mon, 22 Jun 2009 23:16:09 -0600 [thread overview]
Message-ID: <4A406519.7000105@gmail.com> (raw)
In-Reply-To: <1acba2fa0906212354r40122f0i1f1cb50642cf7e23@mail.gmail.com>
On 06/22/2009 12:54 AM, Mahmood Naderan wrote:
> Hi,
> My first question was why CPU states are different from BIOS? If C4
> and C5 are good, why and for what reason, the BIOS does not support
> it. This means that BIOS does not like power saving sates (!)
>
> After that I wondered why my system does not even support C3. So you
> and Edward said that C3 is mapped to C6. It is understanable that OS
> map C3 to C6, but since ACPI is a standard, why should CPU, BIOS and
> OS each one say something different. I am not so expert but I think it
> is a little bit confusing.
It's the BIOS that does the mapping in terms of what C-states are
exposed to the OS. Before ACPI 2.0, only C-states up to C3 were defined.
ACPI 2.0 allows more C-states, but I don't know if Windows actually
supports them. (Not sure if Windows has full ACPI 2.0 support yet.) That
may be why the BIOS people did it that way.
prev parent reply other threads:[~2009-06-23 5:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1acba2fa0906191006i3cd5a035pf18e096fdb92e27e@mail.gmail.com>
2009-06-19 17:07 ` BIOS and CPU C_states are strange Mahmood Naderan
[not found] ` <ff05f3d00906191956m48655da5wc28a5553220ffdd0@mail.gmail.com>
2009-06-20 6:54 ` Mahmood Naderan
[not found] ` <ff05f3d00906210249j6286e6cfw5fff9535e02839e0@mail.gmail.com>
2009-06-21 10:02 ` Mahmood Naderan
2009-06-21 10:13 ` Edward Shao
2009-06-21 10:26 ` Mahmood Naderan
[not found] ` <a8ca10150906200826l37a7ee2fs283ecfa955697c49@mail.gmail.com>
[not found] ` <1acba2fa0906200846r751cf235q9e155e5445090d40@mail.gmail.com>
[not found] ` <a8ca10150906201504p2186b3fbg5ac7761946f48697@mail.gmail.com>
[not found] ` <1acba2fa0906210218o59a6c92fi86e30891c0816b5d@mail.gmail.com>
2009-06-21 9:20 ` Mahmood Naderan
2009-06-21 10:06 ` Edward Shao
2009-06-21 10:14 ` Mahmood Naderan
2009-06-22 1:34 ` yakui_zhao
2009-06-22 6:54 ` Mahmood Naderan
2009-06-23 5:16 ` Robert Hancock [this message]
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=4A406519.7000105@gmail.com \
--to=hancockrwd@gmail.com \
--cc=linux-acpi@vger.kernel.org \
--cc=mahmood.nt@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.