From: Thomas Renninger <trenn@suse.de>
To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: cpuinfo shows wrong MHz value
Date: Mon, 16 Feb 2009 19:13:15 +0100 [thread overview]
Message-ID: <200902161913.16021.trenn@suse.de> (raw)
In-Reply-To: <20090216165008.GA8249@srcf.ucam.org>
On Monday 16 February 2009 17:50:08 Matthew Garrett wrote:
> On Mon, Feb 16, 2009 at 02:19:50PM +0000, Thomas Renninger wrote:
>
> > There should be a message when this driver is loaded like:
> > "This driver is broken. Don't use it, don't complain."
>
> Please don't. It's perfectly valid (if dumb) for machines to depend on
> the CPU for passive cooling even if they don't expose any P or T states.
No it's not valid. If the BIOS does not export these, it could be for
a reason.
> In that case p4-clockmod is the only code that can manage it. The
> removal of the user-visible cpufreq interface should be a strong enough
> hint that it's not intended for speed control.
AFAIK p4-clockmode is still not synchronized with ACPI throttling?
Thus this driver will destroy a valid machine setup where the BIOS exports
throttling states via ACPI.
The driver is broken (and rather useless) and all the complaints about it
get annoying.
I wonder how dangerous it even is. If thermal management on a P4 is
properly implemented via "BIOS throws high temperature MCE and throttles
the CPU itself", could the p4_clockmode driver override the BIOS/HW
settings and still run unthrottled? Danger!
Anyway, I better do not answer on p4_clockmode complaints anymore and
simply delete them, it's just a waste of time.
Thomas
next prev parent reply other threads:[~2009-02-16 18:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-14 21:17 cpuinfo shows wrong MHz value Joerg Platte
2009-02-14 22:29 ` Frans Pop
2009-02-14 22:38 ` Kasper Sandberg
2009-02-14 22:46 ` Frans Pop
2009-02-14 23:22 ` Joerg Platte
2009-02-15 0:02 ` Frans Pop
2009-02-15 7:00 ` Joerg Platte
2009-02-15 7:11 ` Joerg Platte
2009-02-15 16:41 ` Frans Pop
2009-02-16 14:19 ` Thomas Renninger
2009-02-16 16:50 ` Matthew Garrett
2009-02-16 18:13 ` Thomas Renninger [this message]
2009-02-16 18:19 ` Matthew Garrett
2009-02-16 18:47 ` Thomas Renninger
2009-02-16 18:52 ` Frans Pop
2009-02-16 19:01 ` Matthew Garrett
2009-02-18 19:54 ` Joerg Platte
2009-02-18 21:05 ` Frans Pop
2009-02-19 17:03 ` Joerg Platte
2009-02-20 2:52 ` Frans Pop
2009-02-20 18:42 ` Joerg Platte
2009-02-15 17:43 ` Frans Pop
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