[lm-sensors] lm-sensors Digest, Vol 41, Issue 2

Frank Myhr fmyhr at fhmtech.com
Tue Sep 2 16:29:22 CEST 2008

Hector Lahoz Grañena wrote:
> Are there any plans to implement Smartguardian (i.e. fan speed control) for
> the it87 family? Should I write a daemon to control the fans or is the driver
> who has to do the work?
> Another possibility is using the smartguardian automatic mode which has the
> advantage, I think; that it's easy to implement and causes no CPU overload.
> By the way, the programming interface thar appears in the datasheet does not
> correspond to my chip (it8705 version 2). I almost go crazy.

Hi Hector,

I've been working to add automatic fan mode to the it87 driver. It works on the
it8718, but I'm still changing the sysfs interface, and adding auto mode support
for the other it87 chips. I'll post the code to this list when ready. It would
be great if you could help test it on your it8705_v2, I don't have one here.

Auto mode varies a bit from chip to chip, and for the 8705, for different
versions of the chip*. For your it8705_v2, auto mode allows 5 discrete fan
speeds: off, low, medium, high, and all fans full speed. You could get smoother
control by using the software pwm mode you already have working along with the
lm_sensors fancontrol script.

* Note that the datasheet version does not always correspond to the version
that the chip reports in Global Configuration Register 0x22:[3-0]. For

datasheet	chip-reported version
8705 0.3	0x02
8712 0.7	0x06
8712 0.81	0x07
8712 0.9.3	0x08


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