Gunnar Wolf | 4 Oct 17:47
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Bug#501137: ITP: acerfand -- Control the fan of the Acer Aspire One

Package: wnpp
Severity: wishlist
Owner: Gunnar Wolf <gwolf <at> debian.org>

* Package name    : acerfand
  Version         : 0.03
  Upstream Author : Rachel Greenham <rachel <at> strangenoises.org> and others
* URL             : http://home.strangenoises.org/~rachel/aspireone/
* License         : GPL
  Programming Lang: Perl, Shell
  Description     : Rudimentary automatic fan control for noisy Acer Aspire One models

 Keeps the fan from spinning constantly in the noisy Acer Aspire
 One. Provides also tools to query several machine-specific EC
 registers

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)

Matthew Garrett | 5 Oct 03:35

Bug#501137: ITP: acerfand -- Control the fan of the Acer Aspire One

Gunnar Wolf <gwolf <at> debian.org> wrote:

>  Keeps the fan from spinning constantly in the noisy Acer Aspire
>  One. Provides also tools to query several machine-specific EC
>  registers

Be careful with this - it can't perform the locking used by the kernel 
and firmware for EC access, so there's a risk of racing and trashing the 
contents of other registers. This should really be implemented as a 
kernel driver using either the hwmon or thermal interfaces and a generic 
fan control daemon implemented on top of that.

--

-- 
Matthew Garrett | mjg59-chiark.mail.debian.devel <at> srcf.ucam.org

Gunnar Wolf | 8 Oct 00:30
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Bug#501137: ITP: acerfand -- Control the fan of the Acer Aspire One

Matthew Garrett dijo [Sun, Oct 05, 2008 at 02:35:11AM +0100]:
> Gunnar Wolf <gwolf <at> debian.org> wrote:
> 
> >  Keeps the fan from spinning constantly in the noisy Acer Aspire
> >  One. Provides also tools to query several machine-specific EC
> >  registers
> 
> Be careful with this - it can't perform the locking used by the kernel 
> and firmware for EC access, so there's a risk of racing and trashing the 
> contents of other registers. This should really be implemented as a 
> kernel driver using either the hwmon or thermal interfaces and a generic 
> fan control daemon implemented on top of that.

Thanks for the information - Given this, I retract my intention to
package. And given that the package is already packaged and uploaded:
FTP-masters, please ignore/delete it.

Matthew, and out of personal curiosity (as I will probably continue to
use this, at least until something better comes along): What does the
danger amount to? Say, a random lock-up? Or will it lead to hardware
malfunction (or shorter lifespan)? I am currently setting the
fan-on threshold at 70C, the fan-off at 60C (the default settings for
acerfand) 

Thanks!

--

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Gunnar Wolf - gwolf <at> gwolf.org - (+52-55)5623-0154 / 1451-2244
PGP key 1024D/8BB527AF 2001-10-23
Fingerprint: 0C79 D2D1 2C4E 9CE4 5973  F800 D80E F35A 8BB5 27AF
(Continue reading)

Matthew Garrett | 8 Oct 04:21
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Bug#501137: ITP: acerfand -- Control the fan of the Acer Aspire One

On Tue, Oct 07, 2008 at 05:30:12PM -0500, Gunnar Wolf wrote:

> Matthew, and out of personal curiosity (as I will probably continue to
> use this, at least until something better comes along): What does the
> danger amount to? Say, a random lock-up? Or will it lead to hardware
> malfunction (or shorter lifespan)? I am currently setting the
> fan-on threshold at 70C, the fan-off at 60C (the default settings for
> acerfand) 

It really depends on how the hardware is designed, but an example would 
be where the kernel ends up reading the incorrect register when checking 
the temperature and misinterprets it as requiring a critical thermal 
shutdown. Lockups are certainly possible, and it's just about 
conceivable that you could cause hardware damage - though that's a bit 
of a stretch.

--

-- 
Matthew Garrett | mjg59 <at> srcf.ucam.org


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