i8k fan speed values are wrong

[Endolith]

I installed i8kutils and added i8k to my /etc/modules. Now i8k values show up in sensors-applet for both fans, but either i8k reports them incorrectly or sensors-applet interprets them incorrectly, because it says my fans are going at more than 200,000 RPM. Since the sensors-applet graph maxes out at 100,000 for some reason, I can't display them on the graph.

i8kctl gives:

1.0 (null) 86JQQ51 61 2 2 230520 167640 0 2

the "230520 167640" are the fan speeds, and are interpreted by sensors-applet as RPM values. The tooltip says things like "226980RPM"

[Endolith (endolith)]

Oh wait. http://people.debian.org/~dz/i8k/00-README says that the speed is RPM ("8. right fan rpm"), so i8k is reporting the wrong values.

[Benjamin Horstman (yodenss)]

I can confirm this behavior. Running XPS gen 2 laptop. I have other issues with my fans under hardy, see: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/225442

[Tim Morrow (linuxguy6)]

I also can confirm this bug. I am using a Dell Inspiron 8100 with the the latest BIOS and Hardy with the 2.6.24-18 kernel. i8kfan won't let me read the RPM values or control the fans. See bug #238880.

[mihai.ile (mihai.ile)]

confirm this under 8.10 using xps m1330 A15 bios.
Right now it reads 91050 RPM.

Does someone need more info in finding a way to fix it? i'll be glad to give it.

[mihai.ile (mihai.ile)]

Hello again!
That was fast, I know but I think I found the solution:
it seems that i8k is using a I8K_FAN_MULT=30 multiplicator for the fan speed, but newer motherboards already does that, so if using the gnome sensors applet adjust the sensor value multiplier under it's preferences at "0.033" ( the value comes from 1/30).

Now my fan speed is 3005RPM which is a way more trusted value indeed!

Where I got this stuff from: http://lkml.org/lkml/2005/3/12/155

Now the question is how could the i8k be patched not to show the value multiplied on certain motherboards/bioses?

[ebrjvd (jos-van-dyck)]

Ubuntu Lucid 10.04 on Dell Inspiron 5100 with latest bios A32

i8kctl shows wrong RPM value.
Setting I8K_FAN_MULT=30 doesn't have any effect.

[Ben Whitten (benwhitten)]

For those of you with newer motherboards set the i8k module parameter fan_mult to 1 when you load it.
Works for me with my Latitude E5500.

[cement_head (andorjkiss)]

For me too with a DELL e6420 (Maverick Meerkat) 10.10

[Carl (n6rl)]

Affects me too, Dell Latitude E7440.

Loading with module parameter:
sudo modprobe i8k force=1 fan_mult=1
fixes the problem for me as well.

(Remove the module, 'modprobe -r i8k', before adding it with the new parameter for the parameter to take effect.)

[vitorafsr (vitorafsr)]

There is no solution to this bug at the moment as there is no doc that describes how to interpret the values that the module 'i8k' reads.

There is the possibility of multiplying the result of 'i8k' reads by a fixed value, but whether it will function or not is a guess. Some people experience good results with this approach but the values might not be correct. Perhaps they are acceptable.

To the available docs over the internet, I could not find any one that is related to this subject about Dell hardware. If someone has any guindance, please share.

So, now, I consider this bug as 'won't fix' for the moment.

But I'd like to add that, although the speed values are wrong, the temperature values are totally right, and this package fulfill all necessities of many Dell laptop models.