From: Pavel Troller <patrol@sinus.cz>
To: Erik Slagter <erik@slagter.name>
Cc: linux-acpi@vger.kernel.org
Subject: Re: [PATCH] amd76x_pm: C3 powersaving for AMD K7
Date: Fri, 3 Feb 2006 10:33:35 +0100 [thread overview]
Message-ID: <20060203093335.GA4403@tangens.sinus.cz> (raw)
In-Reply-To: <1138958502.18273.1.camel@localhost.localdomain>
> On Wed, 2006-02-01 at 20:35 -0500, Brown, Len wrote:
> > Re: bad timing
> > If the BIOS advertises C2 latency > 100usec, then the BIOS
> > and the system do not support C2.
> > If the BIOS advertises C3 latency > 1000usec, then the BIOS
> > and the system do not support C3.
> > This isn't just a suggestion, it is the standard method
> > that the spec provides the BIOS to tell the OS to NOT USE these states.
>
> Isn't there any other way to tell the operating system that the C2/C3
> states are unusable (e.g. by simply telling they're not there?). This
> looks so obfuscated...
Hi!
The problem is that the table (RSDT) has a fixed format and the values have
reserved positions. Putting 0 there would mean zero (unmeasureble) latency,
which would be the best case, of course. So to disable the feature, "out of
range" method was selected. Yes, it would be nice to have some "special" value
there, like FFFF, but it is not a common practice.
With regards, Pavel Troller
next prev parent reply other threads:[~2006-02-03 9:33 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-02 1:35 [PATCH] amd76x_pm: C3 powersaving for AMD K7 Brown, Len
2006-02-02 1:50 ` Alan Cox
2006-02-02 9:50 ` Erik Slagter
2006-02-02 19:38 ` Tony Lindgren
2006-02-03 9:21 ` Erik Slagter
2006-02-03 9:33 ` Pavel Troller [this message]
2006-02-03 9:39 ` Erik Slagter
2006-02-03 10:14 ` Pavel Troller
2006-02-03 10:28 ` Erik Slagter
-- strict thread matches above, loose matches on Subject: below --
2006-02-03 18:40 Brown, Len
2006-02-04 10:31 ` Erik Slagter
2006-02-04 10:49 ` Pavel Troller
2006-02-03 18:28 Brown, Len
2006-02-03 18:20 Brown, Len
2006-02-03 8:45 Brown, Len
2006-02-03 9:35 ` Erik Slagter
2006-02-03 10:31 ` Pavel Troller
2006-02-03 14:16 ` Joerg Sommrey
2006-02-03 15:59 ` Juhani Rautiainen
2006-02-03 17:02 ` Erik Slagter
2006-02-08 20:10 ` Pavel Machek
2006-02-02 22:24 Joerg Sommrey
2006-02-02 22:37 ` Andrew Morton
2006-02-03 7:03 ` Joerg Sommrey
2006-02-02 22:43 ` Dave Jones
2006-02-01 18:11 Brown, Len
2006-02-01 18:18 ` Erik Slagter
2006-02-01 18:40 ` Tony Lindgren
2006-02-01 19:13 ` Joerg Sommrey
2006-01-31 18:55 Joerg Sommrey
2006-02-01 3:34 ` Andrew Morton
2006-02-01 10:25 ` Erik Slagter
2006-02-01 17:20 ` Tony Lindgren
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