Problem with fans on my laptop

[Spl33n]

Dear linuxforums.org users!

I have noticed a problem with thermal management in Fedora 2.6.23-9 (and also in Ubuntu 2.6.22) and my HP Compaq 6720s laptop with 1,6Ghz Core 2 Duo CPU. If my computer is turned off for at least a few hours - just enough to let it get cold - everything goes okay. When I log into Fedora, I can see that my fans are running quietly at 20% and the temperature of the system is around 48 °C.

BUT, on the other hand, if my computer is still hot or warm when I turn it on, something odd starts happening. After I choose Fedora in GRUB the fan goes off really loud for about 5 seconds and then the system boots, with fan still running at around 50%.
When I log on I notice that my fan is running louder than normal. The sensor tells me that computer is at 50° C. After a minute or so, fan turns off completely (running at 0%) for around 30 seconds, letting the systems to heat up fast again and then fan starts again. This keeps repeating on and on - I don't know how to break the cycle!! It is very disturbing!

The same loop starts if - after a normal cold boot with fan running quitely at 20% - laptop reaches the point of 60°C (ie. beacuse of some heavy gaming or compiling) - then the cycles start again.

If I use the suspend and hibernate modes, the thermal management also goes erratinc, going into loop of heat and cool cycles. (even i wake up when the computer is already cold)

This must some kind of a bug. I am not sure what causes it, or who to blame - kernel, acpi or BIOS - (i am quite sure it is not BIOS, as fan starts behaving bad just after I start loading the linux kernel)

I am out of ideas who to ask about this. As I've seen many problems solved on linuxforum.org, I hope this one could get it's attention...

Regards!

EDIT:
I am sorry for not posting this in the laptops section in linuxforums.org. If anyone can move it - thanks!

[oz]

I am sorry for not posting this in the laptops section in linuxforums.org. If anyone can move it - thanks!

Moved... per your request.