Red Hat Bugzilla – Bug 129413
CPU fan never shuts down on ThinkPad A31p
Last modified: 2015-01-04 17:08:28 EST
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Description of problem:
The CPU fan on my A31p never stops running. It runs 24/7 at full
speed, no matter what the cpu load or temperature.
I suspect it is an ACPI issue since acpi doesn't seem to detect the
cpu fan at all.
The path: /proc/acpi/fan/, is completely empty. I've seen other
laptops have some kind of sensor information in there.
The problem is more evident when the laptop runs on battery, the fan
runs at full speed all the time and thus lowers battery life by 10%!
Running winblowz on the same machine shows that the cpu fan only comes
up at high cpu temperature.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. boot Fedora
2. listen to the fan spin
Actual Results: fan spins constantly
Expected Results: fan spins only when cpu is at a high temperature
IBM ThinkPad A31p
1 gig ram
80 gig hdd
ATI FireGL 7800 M7
Intel Pentium 4 2.0ghz
Fedora Core 2
Same with FC3. Also tested with other kernels... Probably simething
in ACPI ....
Maybe the IBM Power Management driver for Windowz takes care of that
under windoze. In that case, the cpu fan is software controlled and
not controlled by the BIOS or some hardware temperature thingy.
If the fan is controlled via software, then this is a dead issue. IBM
never releases any hardware information for their ThinkPads. One such
example is the lm_sensors util that kills ThinkPads, IBM never helped
solve the problem.
An update has been released for Fedora Core 3 (kernel-2.6.12-1.1372_FC3) which
may contain a fix for your problem. Please update to this new kernel, and
report whether or not it fixes your problem.
If you have updated to Fedora Core 4 since this bug was opened, and the problem
still occurs with the latest updates for that release, please change the version
field of this bug to 'fc4'.
The ibm-acpi project has managed to control the CPU fan, thus making it possible
to turn off and on the fan based on the CPU temperature.