[ltp] Weird CPU fan problem on T400, any help appreciated.

[Mark Altern]

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Before Ubuntu 10.04, I was using 9.10 and the cpu fancontrol is working OK,
without me installing any fancontrol software. I think the BIOS control it
through acpi. It works perfectly.

Now after I did a clean install of 10.04, I found the BIOS doesn't do it
correctly: since the start-up cpu fan speed is about 1886rmp (normal), when
the cpu temp goes to 55c, it cramp up to 2700rmp, then after that even the
cpu have been idle for a long while and temp drop to 37c, the fan wouldn't
slow down, but keep running at that high speed.

Then as suggested by a linux guru friend, I use a Window 7 install DVD to
boot the laptop without doing anything, and then reboot back to Ubuntu
10.04, this time the CPU fan start working correctly, meaning the fan speed
goes up and goes down according to cpu temp. BUT, this lasts only for a
short while, and after running it for a hour, the CPU fan will run high
speed (2738rmp) without slowing down again, even the CPU temp drop to 36C
already.

What possibly is wrong? please give me some guidance, guys.
Thanks a lot.


Lenovo Thinkpad T400,
p8600@2.4Ghz, DDR3@4G, 160G@7200RPM, Intel X4500.

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Before Ubuntu 10.04, I was using 9.10 and the cpu fancontrol is working=20
OK, without me installing any fancontrol software. I think the BIOS=20
control it through acpi.  It works perfectly. <br>
<br>
Now after I did a clean install of 10.04, I found the BIOS doesn&#39;t do i=
t
 correctly: since the start-up cpu fan speed is about 1886rmp (normal), whe=
n the=20
cpu temp goes to 55c, it cramp up to 2700rmp, then after that even the=20
cpu have been idle for a long while and temp drop to 37c, the fan=20
wouldn&#39;t slow down, but keep running at that high speed. <br><br>Then a=
s suggested by a linux guru friend, I use a Window 7 install DVD to boot th=
e laptop without doing anything, and then reboot back to Ubuntu 10.04, this=
 time the CPU fan start working correctly, meaning the fan speed goes up an=
d goes down according to cpu temp. BUT, this lasts only for a short while, =
and after running it for a hour, the CPU fan will run high speed (2738rmp) =
without slowing down again, even the CPU temp drop to 36C already. <br>

<br>
What possibly is wrong? please give me some guidance, guys. <br>Thanks a lo=
t. <br><br><br>Lenovo Thinkpad T400, <br>
p8600@2.4Ghz, DDR3@4G, 160G@7200RPM, Intel X4500.
		=09

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