acpi fan does not lower speed when CPU temp is back to low

[Nate Lawson]

Andriy Gapon wrote:
> on 20.09.2004 14:38 Saulius Menkevicius said the following:
> 
>>Is there a way to find why the ACPI code does not lower
>>CPU fan speed when temperature drops back to low (as set in BIOS)?
>>It does turn the speed to 100% when temperature gets high.
>>
>>Can it be a buggy BIOS ACPI? Though it's working fine in Windows.
>>
>>The motherboard is Abit IS7, desktop with a P4 2.4C.
>>Running 5.3-BETA4.
> 
> 
> turning fans on/off is done by OS (kernel), but it is done
> through calling ACPI methods, so the problem can be in either place.
> Try to take dump of your ACPI DSDT (using acpidump) and look for FAN
> device section in there. You can post it to the list or send to me in
> private.
> If you are ineterested, you can also google for ACPI specs and download
> them, they are not very hard to comperehend (but bulky).

Build your acpi module with options ACPI_DEBUG.  Then put this in 
loader.conf:

hw.acpi.verbose="1"
debug.acpi.layer="ACPI_THERMAL"
debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"

Send the dmesg output including any fan events.

BTW, a lot of this info is in the acpi(4) man page and the ACPI 
debugging section of the handbook.

-- 
Nate