[lm-sensors] Reducing fan speed for w83627ehf

Arun Raghavan arraghav at gmail.com
Thu Jun 28 18:21:40 CEST 2012


On Thu, Jun 28, 2012 at 2:31 AM, Jean Delvare <khali at linux-fr.org> wrote:

> On Wed, 27 Jun 2012 18:18:09 -0400, Arun Raghavan wrote:
> > Writing 0 to pwm2 also keeps it at 1054 RPM. I'm setting pwm2_enable to
> 1,
> > isn't that supposed to make it manual? Also, I do see a variation between
> > 1054 RPM and 2109 RPM (and some steps in between), when I change pwm2. I
> > can't get it to spin lower than 1054 RPM though.
>
> 4-wire fans (which are the most popular on CPU cooling blocks these
> days) have an indirect interpretation of the PWM value, which means
> that the fan maker is free to set the minimum speed (PWM = 0) to any
> arbitrary limit they want. In best cases the value is clearly
> documented in the product description sheet or accompanying technical
> documentation.
>
> 1000 RPM is a relatively common value for the minimum speed of CPU
> fans, so I'm not surprised by your observations. If this is too much
> for you, you have to either lower the input voltage to the fan, or use
> a different model altogether.
>
>
Thanks, that makes sense. Can I control the input voltage through
software/some sysfs attribute or do I have to do it from the supply?

thanks,
-arun

--
> Jean Delvare
>
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