[ltp] RE: [ACPI] fan always on: ACPI on IBM ThinkPad R51

[Len Brown]

On Wed, 2004-09-01 at 06:05, susinho@ultreia.org wrote:
> Thank you for this info.
> 
> I opened the laptop and found a three wire connector to the fan, wich
> usually means speed control by BIOS. Disconnecting the fan, a "Fan
> failure" appears and booting process stops. So I supose the fan speed
> and switches are controlled by non-ACPI parts of the BIOS.
> 
> In this case, adding a fan device in the dsdt could make ACPI handle the
> fan?  Is this possible, or the only way is to modify the BIOS?

Such an ACPI device would need methods, and those methods would
read and write platform-specific hardware registers.  This is the
job of the BIOS writer at IBM.  But apparently on this model IBM
has a non-ACPI means to handle the fans, probably an embedded
controller.

-Len

> O 31/8/2004, "Wang, Zhenyu Z" <zhenyu.z.wang@intel.com> escribiu:
> 
> >There is no fan device in your dsdt. That means ACPI fan driver couldn't
> >handle it.
> >