cvs commit: src/sys/dev/acpi_support acpi_ibm.c

[Nate Lawson]

Markus Brueffer wrote:
> Nate Lawson schrieb:
> 
>>Markus Brueffer wrote:
>>
>>>markus      2006-01-14 00:39:10 UTC
>>>
>>>  FreeBSD src repository (ports committer)
>>>
>>>  Modified files:
>>>    sys/dev/acpi_support acpi_ibm.c   Log:
>>>  - Add support for setting the fan control mode to manual or automatic
>>>  - Add support for adjusting the fan speed if the fan control mode is
>>>manual
>>>    Documentation for the relevant embedded controller register was
>>>obtained from
>>>  http://www.thinkwiki.org/wiki/Patch_for_controlling_fan_speed
>>>    Tested on:      R51  by Fabian Keil
>>>                  T41p by markus
>>>  Requested by:   many
>>>  Approved by:    philip
>>>  MFC after:      1 week
>>>    Revision  Changes    Path
>>>  1.10      +55 -3     src/sys/dev/acpi_support/acpi_ibm.c
>>
>>Thanks for adding support for this but it should be noted that this can
>>be very dangerous.  If your userland app tries to control the fanspeed
>>and dies, your system could overheat.  Hopefully, the BIOS will override
>>the user settings if the temp gets too high but that is a longshot when
>>mucking with things at this low level.
> 
> That's why I didn't add support for it in the first place. The problem
> is that especially with the T43 series there seems to be a fan problem.
> If it reaches a certain threshold the fan is switched on, but never
> switched off regardless how cool the notebook gets.

That's probably a bug in acpi_thermal.  It needs a thorough debugging 
anyway.

> If the new documentation in acpi_ibm(4) isn't enough, I can add bigger
> warning signs:
> 
> dev.acpi_ibm.0.fan
>      Indicates whether the fan is in automatic (1) or manual (0) mode.
>      Default is automatic mode.  This sysctl should be used with
>      extreme precaution, since disabling automatic fan control might
>      overheat the ThinkPad and lead to permanent damage if the
> 
> For obvious reasons I haven't tested if the BIOS overrides the user
> settings if the temp gets too high :)

That seems good.  I didn't see the man page update before I replied.

-- 
Nate