For a few weeks, the fans of my Lenovo B590 laptop, running on Xubuntu 14, turn to high speed a few minutes after it is turned on. The fans won't speed down until I turn the computer off.
This is quite strange, since
This didn't happen before
The temperatures are quite low (are they ?)
$sensors
Adapter: Virtual device
temp1: +36.0°C (crit = +88.0°C)
temp2: +30.0°C (crit = +126.0°C)
coretemp-isa-0000
Adapter: ISA adapter
Physical id 0: +37.0°C (high = +72.0°C, crit = +90.0°C)
Core 0: +34.0°C (high = +72.0°C, crit = +90.0°C)
Core 1: +31.0°C (high = +72.0°C, crit = +90.0°C)
thinkpad-isa-0000
Adapter: ISA adapter
fan1: 0 RPM
pkg-temp-0-virtual-0
Adapter: Virtual device
temp1: +37.0°C
$sudo hddtemp /dev/sda
/dev/sda: ST500LT012-9WS142: 33°C
The computer is under low load:
top - 08:30:15 up 16 min, 2 users, load average: 0.28, 0.23, 0.23
Tasks: 197 total, 1 running, 196 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.8 us, 0.5 sy, 0.0 ni, 98.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 3607944 total, 1973956 used, 1633988 free, 99660 buffers
KiB Swap: 3744764 total, 0 used, 3744764 free. 789936 cached Mem
The BIOS is up to date (and there are no fan settings in it)
The fan is clean and dust-free
Why would the BIOS turn the fans to high speed where there seem to be no reason for that ?
It seems that we cannot control the fan manually with this model, so I guess the only solution is to understand why this happens.