Date: Wed, 28 Apr 2004 21:19:08 +0200
From: Dominik Brodowski <linux@dominikbrodowski.de>
To: Ken Ashcraft <ken@coverity.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [CHECKER] Implementation inconsistencies involving writes
Message-ID: <20040428191908.GB4819@dominikbrodowski.de>
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	Ken Ashcraft <ken@coverity.com>, linux-kernel@vger.kernel.org
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On Tue, Apr 27, 2004 at 08:54:15PM -0700, Ken Ashcraft wrote:
> I'm trying to cross check implementations of the same interface for
> errors.  I assume that if functions are assigned to the same function
> pointer, they are implementations of a common interface and should be
> consistent with each other.

> [BUG] <linux@brodo.de> not writing policy->governor. looks like it is
> necessary to write a default value there.

It surely _looks like_ it's a bug, but it isn't. cpufreq drivers can either
have a "->target" or a "->setpolicy" function defined in the cpufreq_driver
struct. If it's ->target, ->governor needs to be set, if it's ->setpolicy,
->governor may not be set, or at least should not be set. As there's only=
=20
one ->setpolicy cpufreq driver (longrun), it's not as clear as it should be.

The difference between target and setpolicy cpufreq drivers is the
following: on the first type, the CPU can be set to run at a specific
frequency. setpolicy drivers can set the CPU to a frequency range; the CPU
itself at which frequency to run within this range -- an interesting featur=
e=20
of Transmeta CPUs, which made this distinction necessary.

	Dominik

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