Most recent kernel where this bug did not occur: dont'know
Distribution: Ubuntu 6.10
Hardware Environment: HP Pavillion dv2172ea Notebook (dv2000 series) Core 2 Duo
CPU, Bios Ver. F.11
Software Environment: Kernel 2.6.17, Gnome 2.16.1
Problem Description: Using Windows XP gets about 3 hour battery life, the fan
runs often (at lowest speed) but stops when the pc is idle for sometime.
Using Linux gets about 2 hour battery life, the fan is always on (at lowest
speed) and never stops.
Running non processors intensive tasks (Firefox, Thunderbird, Gaim) easily get
the fan to a higher speed level.

If cold booting (when the PC has been off for hours) the fan does stop for
sometime, but only for a few minutes, when the PC gets to its normal running
temperature it goes on and never stops.

Steps to reproduce: Just boot Linux and wait, the fan goes on and never spins down.

Temperatures from the 2 thermal zones are always around 50C or few degrees below
(even when idle)
if stress testing I can get a few degrees past 80C

I get this reading from cat /proc/acpi/thermal_zone/TZS*/*

<setting not supported>
cooling mode:   critical
<polling disabled>
state:                   ok
temperature:             49 C
critical (S5):           98 C
<setting not supported>
cooling mode:   critical
<polling disabled>
state:                   ok
temperature:             51 C
critical (S5):           120 C

I don't know if it's the fan control which is problematic or if the fan control
is ok but the temperatures are too high, triggering the fan always on.
I constantly monitor CPU usage with top -d1 and/or gkrellm and there isn't any
background task hogging the cpu.