[ltp] [T410s] Fan running constantly

[Daniel Näslund]

Hi,

I have a Lenovo Thinkpad T410s. When the temperature, as reported by
/proc/acpi/ibm/thermal, reaches a little over 40 degrees, the fan
starts running and never stops. The temperature typically stays around
40-45 degrees even when the laptop is idle.

I have tried changing the settings in BIOS from 'Performance' to
'Balanced' for Config->AC power mode but no change in fan speed. I'm
running the latest BIOS version as of today, 1.41.

I booted with acpi=off as suggested by [1]. The fan still spins at
high speed and doesn't stop despite the computer beeing idle for ten
minutes. Should I then assume that the T410s has a fan that is not
controlled by acpi? (In that case, I'm a little surprised that all the
/proc files associated with fan control shows up in the filesystem).

When googling, I find several forum posts describing the T410s fan as
noisy when running Linux but it appears as  a non-issue for Windows
users. Has anyone found a workaround? I've found [2] but I'm resistant
to alter the behaviour of the fan without some feedback from other
users.

I'm currently running 2.6.35-28 kernel supplied by Ubuntu. When executing

    git diff v2.6.35 -- drivers/platform/x86/thinkpad_acpi.c

on an updated kernel tree I can see some changes but nothing that
appears to be related to fan control. Has anyone used one of the more
recent kernels and what are your experience with regards to fan speed?

Some data reported by proc:

$ grep . /proc/acpi/thermal_zone/*/*
/proc/acpi/thermal_zone/THM0/cooling_mode:<setting not supported>
/proc/acpi/thermal_zone/THM0/polling_frequency:<polling disabled>
/proc/acpi/thermal_zone/THM0/state:state:                   ok
/proc/acpi/thermal_zone/THM0/temperature:temperature:             44 C
/proc/acpi/thermal_zone/THM0/trip_points:critical (S5):           100 C
/proc/acpi/thermal_zone/THM0/trip_points:passive:                 85
C: tc1=5 tc2=4 tsp=600 devices=CPU0 CPU1 CPU2 CPU3

$ grep . /proc/acpi/*/*
/proc/acpi/ibm/beep:status:		supported
/proc/acpi/ibm/beep:commands:	<cmd> (<cmd> is 0-17)
/proc/acpi/ibm/bluetooth:status:		enabled
/proc/acpi/ibm/bluetooth:commands:	enable, disable
/proc/acpi/ibm/cmos:status:		supported
/proc/acpi/ibm/cmos:commands:	<cmd> (<cmd> is 0-21)
/proc/acpi/ibm/driver:driver:		ThinkPad ACPI Extras
/proc/acpi/ibm/driver:version:	0.24
/proc/acpi/ibm/fan:status:		enabled
/proc/acpi/ibm/fan:speed:		4024
/proc/acpi/ibm/fan:level:		auto
/proc/acpi/ibm/hotkey:status:		enabled
/proc/acpi/ibm/hotkey:mask:		0x078c7fff
/proc/acpi/ibm/hotkey:commands:	enable, disable, reset, <mask>
/proc/acpi/ibm/led:status:		supported
/proc/acpi/ibm/led:commands:	<led> on, <led> off, <led> blink (<led> is 0-15)
/proc/acpi/ibm/light:status:		off
/proc/acpi/ibm/light:commands:	on, off
/proc/acpi/ibm/thermal:temperatures:	43 0 0 0 0 0 0 0
/proc/acpi/ibm/wan:status:		enabled
/proc/acpi/ibm/wan:commands:	enable, disable
/proc/acpi/ibm/volume:level:		unsupported
/proc/acpi/ibm/volume:mute:		off

Daniel

[ 1] http://www.lesswatts.org/projects/acpi/debug.php
[2] http://www.thinkwiki.org/wiki/How_to_control_fan_speed