fans run constantly: bad fan management or hot laptop?

[johnrobert]

The fan runs constantly on my new Dell Studio 1557 with an i7 processor. In Windows it runs occasionally, but the minute I reboot into Kubuntu the fan(s?) come on and stay on. Very annoying.

Following instructions that I found on the "Linux ACPI Howto" at http://www.columbia.edu/~ariel/acpi/acpi_howto.html, I ran

sudo cat /proc/acpi/thermal_zone/*/trip_points

and got this:

critical (S5): 127 C
critical (S5): 85 C
passive: 95 C: tc1=0 tc2=10 tsp=2 devices=CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
active[0]: 71 C: devices=FAN1
active[1]: 55 C: devices=FAN0

Now part of what bothers me is that when I run

sensors

I get temp1 equal to 26.8 and temp2 equal 46.0, both of which are well below the temperatures that would trigger the fans if I'm reading the trip_point outputs correctly. But I also ran

sudo cat proc/acpi/thermal_zone/*/polling_frequency

and got <polling disabled> for both of the sensors. So are they working, and if so where can I read their output?

I don't know where I stand now. If the sensors output is right then my fans shouldn't be coming on all the time. But if my fans are responding to the machine's real temperature then I need to find out why the laptop is running so hot all the time. It does feel hotter under Kubuntu, but I'm not at all sure that it's hot enough to justify constant fanning.

Can anyone suggest a next step for me on this?

[kjjjjshab]

Re: fans run constantly: bad fan management or hot laptop?

You are sure it isn't a graphics fan? (Mind you, I have no idea as to whether or not a laptop even has a separate fan for graphics, but generally speaking, without the proprietary driver loaded you can see this behavior for a desktop graphics card).

[johnrobert]

Re: fans run constantly: bad fan management or hot laptop?

Boy, you got me there. There's no mention of a graphics fan in the specs that I looked at.

In any case the problem seems to be better now that I have my wireless working so that I boot straight into Kubuntu now without firing up Windows first. I don't know why that would be, but somehow I'm not surprised.

Thanks for the reply.

[raffytaffy]

Re: fans run constantly: bad fan management or hot laptop?

The nvidia driver shipped with karmic ( 185) is known to keep running the gpu fans on full blast after heavy load. To solve this problem try to use the 190 or 195 driver. I had same issue and 195 driver solved my problem.