Miss fan value interpretation at it8712: 168750 RPM

[ticket]

it8712-isa-0290 Adapter: ISA adapter

fan1: 168750 RPM (min = 811 RPM, div = 8) ALARM

I don't know why but my CPU fan showed as running crazy speeds. Some times I read "-1" and "84375" RPM too. Most of time it shows correct speed. Fan is not broken (tested under win, and there is no problem).

using SuSE 10.2 x86_64 with kernel 2.6.19.1, lm_sensors version 2.10.1 (comes with SuSE)

[ruik]

Hi,

Perhaps the counter overflows because the fan is spinning too low. What is the typical RPM in Windows or BIOS?

You may try to set up higher divisor (instead of 8 use 16 32 64 or 128)

Edit correct sections of /etc/sensors.conf add this line:

set fan1_div 32

Run:

sensors -s
sensors

This should fix it.

Rudolf

[ticket]

What revision of chip is it?

See my post here to see if the attached patch fixes your issue:  http://lists.lm-sensors.org/pipermail/lm-sensors/2008-June/023530.html

Andrew Paprocki <andrew at ishiboo.com>

[khali]

This could also be the same problem as reported here:

 http://lists.lm-sensors.org/pipermail/lm-sensors/2008-May/023247.html

My patch won't fix it (it only affects 16-bit fan speeds not 8-bit ones) but a similar fix could work.

Unfortunately the original report isn't very detailed (we don't know how frequently the problem happens nor whether fan speed control is used) and the author didn't add his address to the Cc field so it's unlikely he will answer our questions 1 year after opening the ticket.

[ruik]

no reply