[NTLUG:Discuss] Re: fan frequency and duration -- proprietary PC notebooks ...

[Bryan J. Smith]

On Thu, 2004-11-04 at 08:28, Fred James wrote:
> All
> Mandrake Linux 9.1 or 10.0 on a laptop (Gateway 450SX4)
> Is there a way to adjust the frequency and duration of the running of 
> the chassis fan?  I have not found anything on the fan in BIOS.
> I am concerned that the fan does not seem to run as much under Linus as 
> it did under the Windows in stall.
> Thank you in advance for any help you may be able to offer

I have a saying, PC notebooks have become more proprietary than Apple
iBooks/PowerBooks.  There is a long story behind that which involves
OEMs, distributors and how closed software is written I won't get into.

With that said, there are kernel facilities for ACPI in kernel 2.6. 
While ACPI is well documented for desktops and standard mainboards-
chipsets -- largely because the 16-bit Real86 BIOS is still included. 
Newer PC notebooks tend to be far more proprietary, utterly lacking nay
16-bit Real86 BIOS compatibility.  Long story short, notebooks are
designed to be limited to specific versions of Windows (again, largely
for control of the distribution channel, not so much anti-Linux). 
Fortunately, various, undocumented ACPI interfaces are reverse
engineered all-the-time and, again, kernel 2.6 helps a lot.

Otherwise, seem if there is a set of kernel/user-space functions for
your specific, tier-1 OEM.  PC OEMs who sell a majority of their systems
in notebook form-factors tend to have their own, standard logic. 
Toshiba is one.  Support for the Toshiba notebooks have been in the
stock kernel since mid-2.4 releases and the user-space components to
handle the backlight, fan, etc... are available.

In the case of Gateway, they tend to purchase one of the 3-4 common
Tawainese manufacturer models and make *0* modifications -- typically
the same as many tier-2 PC OEMs, and possibly 1-2 other tier-1s.  If you
can discover the _exact_ make/model of the _actual_ Tawainese vendor,
you might be able to find out if the specifications are available
(typically not), or at least that someone has reverse engineered some of
the on-board logic (more likely).

I will research the Gateway 450SX4 and get back to you.


-- 
Bryan J. Smith                                  b.j.smith at ieee.org 
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