Check that Laptop Fan is Functioning Correctly on Linux

Question

I just completely disassembled and reassembled my Dell Studio 1555 laptop. I had to remove the hard drive, WLAN card, unplug optical drive, display connector, even the motherboard to get to the fan.

I replaced the fan with a brand new fan, and everything seems to be working fine because I'm using the computer right now to type this. However, I want to check that the fan is functioning correctly because I don't hear it running and the fan speed isn't showing up when using sensors from the terminal.

Is there a way that I can be assured that the fan is functioning, e.g. get a fan speed when sensors is only showing temp1 and temp2?

The critical temp for both CPUs is 100 degrees Celsius and I'm at 54 and 46, so I'll have to power down soon if I can't figure this out.

Answer 1

I didn't really find a robust solution, other than to wait and monitor the fan temperatures via sensors in the terminal.

I can however provide a few things that were useful:

• I ran sudo sensors-detect and said YES to probing everything
• I saw that lm-sensors was going to add coretemp to /etc/modules so I did a sudo modprobe coretemp to avoid restarting to load the module
• I installed XSensors as a GUI for live CPU temperatures: sudo apt-get install xsensors
• I installed a hardware information GUI: sudo apt-get install hardinfo, which showed some awesome information, even did hardware profiling

The key was just to wait about an hour and make sure the CPUs weren't going near the critical temp

Answer 2

There is a specific package for Dell laptops, i8Kutils, that gives you utilities to control/report fan speed. It is quite old but works fine on my Dell M4500:

sudo apt-get install i8kutils 
sudo modprobe i8k
sudo i8kfan 0 1 

Also have a look at dellfand. Note that I had to add #include <sys/stat.h>to dellfand.cc to get it to compile. Once installed you can play with the fan speeds. eG:

sudo ./dellfand 0 3 40 50 65
sudo ./dellfand 0 0.2 25 40 65

Answer 3

Here is a free to try demo of 'Speed fan'. Among other things it can do, you can set temps for the fan to come on, check mobo temps and the like.

Speedfan

If you set the critical temp low (say 28 - 30), it should kick the fan on way before needed. This would allow you to monitor temp and feel the fan kick on.