[ltp] Re: pwm controls in /sys
Dave Cunningham
linux-thinkpad@linux-thinkpad.org
Sat, 27 Apr 2013 13:00:34 -0400
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Did some more experimentation -- this is how it seems to behave:
pwm1_enable == 0
fan speed: 3800rpm
pwm1_enable == 1
fan speed: 3100rpm to 0 depending on value in pwm (255 to 0)
pwm1_enable == 2
fan speed varies automatically according to temperature, but is never above
3100
Are those RPMs too low? Does this mean I need a new fan?
Even at 3800rpm the laptop goes into thermal shutdown if I run a burnP6 on
each core. The cores are over 90degrees according to sensors. It takes a
while before it goes into thermal shutdown so I guess the heat pipe is
working but the fan isn't carrying the heat away fast enough.
I also have experienced thermal shutdowns doing real workloads like
parallel builds.
thanks
On Sat, Apr 27, 2013 at 12:27 PM, Dave Cunningham <sparkprime@gmail.com>wrote:
> 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">Did some more experimentation -- this is how it seems to b=
ehave:<div><br></div><div>pwm1_enable =3D=3D 0</div><div style>fan speed: 3=
800rpm</div><div style><br></div><div style>pwm1_enable =3D=3D 1</div><div =
style>fan speed: 3100rpm to 0 depending on value in pwm (255 to 0)</div>
<div><div><br></div><div>pwm1_enable =3D=3D 2</div></div><div style>fan spe=
ed varies automatically according to temperature, but is never above 3100</=
div><div style><br></div><div style>Are those RPMs too low? =A0Does this me=
an I need a new fan?</div>
<div style><br></div><div style>Even at 3800rpm the laptop goes into therma=
l shutdown if I run a burnP6 on each core. =A0The cores are over 90degrees =
according to sensors. =A0It takes a while before it goes into thermal shutd=
own so I guess the heat pipe is working but the fan isn't carrying the =
heat away fast enough.</div>
<div style><br></div><div style>I also have experienced thermal shutdowns d=
oing real workloads like parallel builds.</div><div style><br></div><div st=
yle>thanks</div><div style><br></div></div><div class=3D"gmail_extra"><br>
<br><div class=3D"gmail_quote">On Sat, Apr 27, 2013 at 12:27 PM, Dave Cunni=
ngham <span dir=3D"ltr"><<a href=3D"mailto:sparkprime@gmail.com" target=
=3D"_blank">sparkprime@gmail.com</a>></span> wrote:<br><blockquote class=
=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padd=
ing-left:1ex">
<div dir=3D"ltr">I have a w700ds with the thinkpad_hwmon module, and I'=
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>Does anyone understand the /sys interface or know where docu=
mentation can be found?</div><div><br></div><div><div>/sys/class/hwmon/hwmo=
n0/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>Setting pwm1_enable to 0 seems to turn the fan=
up to max, setting it to 1 seems to turn it up 'a bit'. =A0I haven=
't seen pwm1 have any effect. =A0It could be buggy on my hardware but I=
don't know what it's supposed to be doing so can't tell :)</di=
v>
</div></div>
</blockquote></div><br></div>
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