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From: Ben Hutchings <ben@decadent.org.uk>
To: "Dave Jones" <davej@redhat.com>, "Rafał Bilski" <rafalbilski@interia.pl>
Cc: cpufreq@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Is e_powersaver safe to auto-load?
Date: Sat, 11 Feb 2012 23:33:10 +0000	[thread overview]
Message-ID: <1329003190.325.78.camel@deadeye> (raw)

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The e_powersaver driver comes with a dire warning in Kconfig help:

    VIA C7 Enhanced PowerSaver (DANGEROUS)

    This adds the CPUFreq driver for VIA C7 processors.  However, this driver
    does not have any safeguards to prevent operating the CPU out of spec
    and is thus considered dangerous.  Please use the regular ACPI cpufreq
    driver, enabled by CONFIG_X86_ACPI_CPUFREQ.

Following the bug report <http://bugs.debian.org/566208>, Debian's
cpufrequtils init script was changed to stop loading it.  The driver was
later disabled in Debian kernel configurations.  Rafał appears to have
made it somewhat safer since then, but the help text has not been
changed.

Since commit fa8031aefec0cf7ea6c2387c93610d99d9659aa2 ('cpufreq: Add
support for x86 cpuinfo auto loading v4') the driver will be auto-loaded
on some systems.  If it is still dangerous then it should surely not be
auto-loaded.  But if it is now believed to be safe then the help text
should be updated to say so.

Ben.

-- 
Ben Hutchings
The two most common things in the universe are hydrogen and stupidity.

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             reply	other threads:[~2012-02-11 23:33 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-11 23:33 Ben Hutchings [this message]
2012-02-12 12:30 ` Is e_powersaver safe to auto-load? Rafał Bilski
2012-02-22  1:13 ` Rafał Bilski

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