From: Dave Jones <davej@suse.de>
To: Magnus Sandberg <Magnus.Sandberg@bluelabs.se>
Cc: <arjanv@redhat.com>, <linux-kernel@vger.kernel.org>
Subject: Re: Changing CPU Speed while running Linux
Date: Wed, 13 Jun 2001 15:49:51 +0200 (CEST) [thread overview]
Message-ID: <Pine.LNX.4.30.0106131544410.19499-100000@Appserv.suse.de> (raw)
In-Reply-To: <20010613134111.B126C17C7@mailrelay.bluelabs.se>
On Wed, 13 Jun 2001, Magnus Sandberg wrote:
> I have a brand new Dell Inspiron 8000, laptop. It can run in 700 MHz or
> 850 MHz. The manual says that the machine/BIOS switches speed dependent on
> CPU load. I have not installed Linux yet, but it works with Win2000.
Intel Speedstep iirc. My Vaio also has it. My findings so far:
On mains it runs at 700MHz, whilst on batteries it drops to ~550MHz.
If I boot an ACPI enabled kernel, the speed changes according to CPU
load, but with a smaller window. I've seen it go as low as 50MHz,
but only up to a maximum of 200MHz. The fact that it only has a maximum
of 200MHz in this mode probably explains the need for the no-idle switch
in the current ACPI implementation.
As there are no public documents on Speedstep, it's not clear to me
whether this is a limitation of Speedstep, or the ACPI implementation.
Judging by the fact that Windows seems to run at full speed, I'd
be inclined to think the latter.
regards,
Dave.
--
| Dave Jones. http://www.suse.de/~davej
| SuSE Labs
next prev parent reply other threads:[~2001-06-13 13:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-06-13 12:35 Changing CPU Speed while running Linux Sven Geggus
2001-06-13 13:21 ` Arjan van de Ven
2001-06-14 13:12 ` Pavel Machek
2001-06-16 10:46 ` arjan
2001-06-16 13:23 ` Alan Cox
2001-06-16 13:56 ` Ian Stirling
2001-06-13 13:41 ` Magnus Sandberg
2001-06-13 13:49 ` Dave Jones [this message]
2001-06-13 22:23 Dieter Nützel
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