[ltp] fan always on, t41, xubuntu

[Laurent Gilson]

Hello,

>> nope. Just make sure the fan is enabled if any sensors get hot  
>> (/proc/ibm/thermal). Use a failsafe script that enables the fan on  
>> exit. And NEVER EVER kill that process with kill -9.
>
> Ok, got the tp-fancontrol scripts working. Now I'd like to see it in  
> work before I leave it alone. Thought aout compiling a kernel, and  
> watching the temperature go up and the fan kick in.

A little bash-line will do the same:
while (true); do : ; done

> I looked in /proc/acpi/thermal_zone/THM0/temperature, and it's pretty  
> low right now 37C.

Thatīs only the CPU.

> Is the a reliable source for testing?

/proc/acpi/ibm/thermal is better. It monitors other stuff too, like GPU,  
WLAN/Mini-PCI, HD, ... which all depend on the same fan. The fan triggers  
if any of these get too hot.

> "cat /proc/acpi/ibm/thermal" says "37 46 32 47 36 -128 33 -128", what do  
> these figures correspond to

nobody really, really 100% knows: http://ibm-acpi.sourceforge.net/README .  
My guess: the 47 is the GPU. That one triggers the fan at 49°C and stops  
it around 40°C. Didnīt you enable the powersaving mode ? And which card  
and drivers do you use ?

> , and which ones should I stare at while compiling a kernel?

The one rising fast. My CPU goes from 44°C to 70°C in about 30 secs (i  
played with undervolting, so i guess you will see an even quicker rising).  
For all other components the redline is around 50°C. A bit higher for the  
GPU (depends on the model), a bit lower for the HD.

> What should the temperature be before the fan kicks in? Supposed the fan  
> stays off and the temperature keeps rising, at what temperature should I  
> stop my experiment, IOW what's the maximum recommended temperature of  
> the CPU?

70°C for the CPU and 50°C for all other.

The critical/problematic point is the switch-the-fan-off-again  
temperature. IBM has set these very, very low. Too low for most people.  
The scripts in thinkwiki use higher switch-off points. Thatīs how they  
reduce the fan-usage.

> Also; how should the bios cpu frequency scaling + other power related  
> stuff be configured?

Not at all. The moment linux loads the kernel disables everything that was  
configured by the BIOS and makes itīs own rules  
(/sys/devices/system/cpu/cpu0/cpufreq/). So the BIOS-Setup only manages  
the ~5 secondes while the bootloader asks "windows or linux ?".

cu