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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

  reply	other threads:[~2009-02-16 18:13 UTC|newest]

Thread overview: 23+ 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
2009-02-20 18:42                           ` Joerg Platte
2009-02-15 17:43               ` Frans Pop

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