loud fan on Ubuntu 14.04

Question

I have a Dell Latitude E5420 laptop which I upgraded from Ubuntu 13.10 to Ubuntu 14.04 a few days ago.

I can't help noticing a new annoying behaviour of the fan: it repeatedly gets loud every 1-2 seconds, it turns off, and then on again, for minutes and without any intensive-CPU process running.

Is there any fix for this?

Ok, so the temperature does seem to increase a little bit during these loud moments. It goes quickly from 50 to 60 degrees celsius, and then it cools off and goes back to 50.

It just had never happened so often before...

Noisy:

$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:        +25.0°C  (crit = +107.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +55.0°C  (high = +80.0°C, crit = +85.0°C)
Core 0:         +55.0°C  (high = +80.0°C, crit = +85.0°C)
Core 1:         +54.0°C  (high = +80.0°C, crit = +85.0°C)

i8k-virtual-0
Adapter: Virtual device
Right Fan:   121350 RPM
CPU:          +59.0°C  

Quiet:

$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:        +25.0°C  (crit = +107.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +49.0°C  (high = +80.0°C, crit = +85.0°C)
Core 0:         +51.0°C  (high = +80.0°C, crit = +85.0°C)
Core 1:         +51.0°C  (high = +80.0°C, crit = +85.0°C)

i8k-virtual-0
Adapter: Virtual device
Right Fan:      0 RPM
CPU:          +50.0°C  

This user, with a similar notebook model (Dell Latitude E6400), is having the exact same issue.

EDIT 2. Now the fan has been turning itself on and off for minutes, but the temperature is stable at 42 degrees Celsius:

$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:        +25.0°C  (crit = +107.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +41.0°C  (high = +80.0°C, crit = +85.0°C)
Core 0:         +40.0°C  (high = +80.0°C, crit = +85.0°C)
Core 1:         +40.0°C  (high = +80.0°C, crit = +85.0°C)

i8k-virtual-0
Adapter: Virtual device
Right Fan:   102210 RPM
CPU:          +42.0°C 

EDIT 3. I updated the Dell BIOS to the latest version (from 5 to 14), but to no avail. If I run the fan test with fwts, one test fails and 5 succeed. I can't get a more verbose output, though...

$ fwts fan
Running 1 tests, results appended to results.log
Test: Simple fan tests.                                                     
  Test fan status.                                        5 passed, 1 failed             
  Load system, check CPU fan status. 

Answer 1

After a bit of search and research I have found a reasonable solution, well 2.
1 There are fans that you can replace that are silent. 2 I dug up a website that follows the i8k dell fan/cpu driver. http://www.cyberciti.biz/faq/controlling-dell-fan-speeds-temperature-on-ubuntu-debian-linux/

I have tested this on 14.04 LTS and it does work as I do have an Inspirion 15 3521.

After you install this read this Please note that the service /etc/init.d/i8kmon starts i8kmon in daemon mode. So setting the speed with i8kfan is pointless since the daemon will override the speed with its own value on fly as per system temperature.

Hope this is useful.

Oh, i8kctl fan The fan command can accept two optional parameters which specify the new fan state for left and right fans. The state parameter can be: Where,

0 : turn the fan off (not recommended)
1 : set low speed
2 : set high speed
- : don't change the state of this fan

For example, the following command sets the left fan (usually used by CPU) to high speed and leaves the right unchanged:$ i8kctl fan 2 -

Answer 2

From this answer:

2. You'll probably notice that the fan runs at high speed at all times. I found several websites explaining how to use the "i8kutils" packages to manage fan speed, and the solution appears to work well. For example: http://ubuntuforums.org/showthread.php?t=842775 Load the module was required for the fan settings to take effect: sudo modprobe i8k.

My configuration file (/etc/i8kmon.conf) looks like:

# Run as daemon, override with --daemon option
set config(daemon) 1

# Automatic fan control, override with --auto option
set config(auto) 1

# Status check timeout (seconds), override with --timeout option  
set config(timeout) 2

# Report status on stdout, override with --verbose option
set config(verbose) 1

# Temperature thresholds: {fan_speeds low_ac high_ac low_batt high_batt}
set config(0) {{0 0} -1 55 -1 55}
set config(1) {{0 1} 50 60 55 65}
set config(2) {{1 1} 55 80 60 85}
set config(3) {{2 2} 70 128 75 128}

# end of file

I've been keeping an eye on the core temps to make sure that the fan settings are sane, and they appear to be. To this end:

sudo apt-get install lm-sensors
sudo sensors-detect

followed by installation of the Hardware Sensors Indicators,

sudo add-apt-repository ppa:alexmurray/indicator-sensors
sudo apt-get update
sudo apt-get install indicator-sensors

For reference and comparison of hardware, here is the output from lspci:

00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Ivy Bridge PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4)
00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Device 682f
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 07)
08:00.0 Network controller: Intel Corporation Centrino Wireless-N 2230 (rev c4)