pwm fan control with IT8705F I/O chip it87 module

Mark Studebaker mds4 at
Tue Dec 7 22:10:39 CET 2004

doc/chips/it87 explains how to configure PWM.

Troy Will wrote:
>                    Novmember 28, 2004
> Hello,
> I've been attempting to control the fan speed on a
> Biostar iDEQ 210V computer which has an IT8705F Super
> I/O chip. Does the it87 module ( which controls the
> IT8705F chip ) enable pwm motor fan control? I have
> read similar queries but haven't read any definitive
> answers.
> The it87 documentaton says this: "The fan control
> features can be enabled by setting bits 0-2 of the
> fan_ctl register to 1." However, the documentation is
> silent on how to set this these bits. Can these
> register bits be set with isaset? Can they be set
> somehow in the /etc/sensors.conf file?
> Similarly, the it87 documentation says this: "Bit 7 of
> the pwm[1-3] registers enables/disables the chips
> automatic temperature control mode for the specified
> fan." But again, it has no mention on how to set or
> read these registers.
> Any help would be apprecitated. By the way, I can read
> the fan speed. Since I'm sure other people are trying
> to do the same thing I will set up the following web
> page if I come up with a solution:
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