[ltp] pwm controls in /sys

Dave Cunningham linux-thinkpad@linux-thinkpad.org
Sat, 27 Apr 2013 12:27:52 -0400


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I have a w700ds with the thinkpad_hwmon module, and I'd like to control the
fan manually.  It seems to be dying since the cpu is always overheating but
I can stop my laptop from going into thermal shutdown by more aggresively
turning up the fan.

Does anyone understand the /sys interface or know where documentation can
be found?

/sys/class/hwmon/hwmon0/subsystem/hwmon2/device$

cat pwm1
255
cat pwm1_enable
2


Setting pwm1_enable to 0 seems to turn the fan up to max, setting it to 1
seems to turn it up 'a bit'.  I haven't seen pwm1 have any effect.  It
could be buggy on my hardware but I don't know what it's supposed to be
doing so can't tell :)

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<div dir=3D"ltr">I have a w700ds with the thinkpad_hwmon module, and I&#39;=
d like to control the fan manually. =A0It seems to be dying since the cpu i=
s always overheating but I can stop my laptop from going into thermal shutd=
own by more aggresively turning up the fan.<div>
<br></div><div style>Does anyone understand the /sys interface or know wher=
e documentation can be found?</div><div style><br></div><div style><div>/sy=
s/class/hwmon/hwmon0/subsystem/hwmon2/device$</div><div><br></div><div>
cat pwm1</div><div>255</div><div>cat pwm1_enable=A0</div><div>2</div><div><=
br></div><div><br></div><div style>Setting pwm1_enable to 0 seems to turn t=
he fan up to max, setting it to 1 seems to turn it up &#39;a bit&#39;. =A0I=
 haven&#39;t seen pwm1 have any effect. =A0It could be buggy on my hardware=
 but I don&#39;t know what it&#39;s supposed to be doing so can&#39;t tell =
:)</div>
</div></div>

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