From: Wes Felter <wesley@felter.org>
To: cpufreq@lists.linux.org.uk
Subject: Re: voltage tables
Date: Tue, 31 Jul 2007 14:56:29 -0500 [thread overview]
Message-ID: <f8o4nh$u2o$1@sea.gmane.org> (raw)
In-Reply-To: <200707302241.29635.lenb@kernel.org>
Len Brown wrote:
> On Monday 30 July 2007 19:04, markus reichelt wrote:
>> Hi,
>>
>> just a thought.... with more and more people wondering why cpufreq
>> doesn't work on their over/underclocked systems, what about offering
>> the possibility to use static (and thus easily tweakable) voltage
>> tables instead of/parallel to the ACPI-approach?
[snip]
> Going forward, I believe that the hardware guys have no plans to
> maintain any sort of reasonable compatibility or even straightforward
> decoding of the bit pattern that gets written to PERF_CTL --
> so the reason that speedstep-centrino and its hard-coded tables
> became deprecated will be even more true in the future.
User-provided tables != hard-coded tables. What if acpi-cpufreq dumped
the ACPI table in some semi-human-readable format and then allowed the
user to tweak it (by guessing, since the hardware is undocumented) and
then push the tweaked table back into the driver at runtime? The driver
would still not contain any tables and thus the old speedstep-centrino
maintenance problem would not exist.
There is a patch for speedstep-centrino that adds an op_points_table
file in sysfs; it could be ported to acpi-cpufreq.
http://gentoo-wiki.com/HOWTO_Undervolt_a_Pentium_M_CPU#Getting_the_current_voltage_settings
> Further, I've not played with this, but my understanding is that
> on the Extreme parts, the way to over-clock them is to have
Most overclockers buy cheap non-extreme parts and set the FSB frequency
out of spec; that's why the ACPI tables are wrong.
Wes Felter - wesley@felter.org
next prev parent reply other threads:[~2007-07-31 19:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-30 23:04 voltage tables markus reichelt
2007-07-31 2:41 ` Len Brown
2007-07-31 19:56 ` Wes Felter [this message]
2007-10-11 15:43 ` Nebojsa Trpkovic
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