Thinkpad T420s - Fan not running, at all

laxsu19 · 2012-05-30 14:13:46

Hi all,
Since either a kernel upgrade or maybe just recent travelling I've done (if its a mechanical problem),
I've not been able to use my laptop for more than an hour or so before it shuts itself down due to
excessive heat.
I noticed I hadn't heard the fan, so I went digging around in ACPI and all the Thinkfan settings.
ACPI reports that the fan is running at 65535 RPM which is definitely a suspect number. The fan level is set to 4 right now according to proc/acpi/ibm/fan.
I've tried changing those values, rebooting in to the fallback kernel and the LTS kernel and none of them do me any good.
I have thinkfan and tp_smapi installed and loaded via modprobe.
Does anyone have any suggestions for how to get this thing working?

Thanks,
Adam

Trilby · 2012-05-30 14:24:29

That's a high speed for acpi to report - I suspect it is the harware's max speed (you should be able to check this). You'd HEAR that running.

If the fan is not running but acpi is setting a high fan speed, it is probably broken hardware. It could be as simple as a loose connection - there's not a whole lot that can go wrong with a fan.

alexcriss · 2012-05-30 15:24:59

I believe that your fan doesn't work as it should and that you have an hardware problem. I saw the same symptoms ago, and after a few times seeing the speed at 65535 the system started to hang at boot time saying "Fan error".
Try to contact Lenovo's support and see if they will replace your fan.

Having said that, the fan on T420s is an epic problem, if you feel like helping could you check this?
http://forums.lenovo.com/t5/T400-T500-a … d-p/443569

donniezazen · 2012-05-30 17:31:10

I don't know if this is related but I have noticed that thinkfan which was working perfectly wouldn't start on its own at boot as a daemon. I starts fine manually without any error. On my system location a sensor keeps changing which sometimes shuts it off.

What is your output for following command?

sudo thinkfan -n

btw what programs are you running because it won't shut down until temp is over 100C?

laxsu19 · 2012-05-31 14:54:14

I think I'm believing its hardware now too. I put my warranty request in, should be getting the box today.

donniezazan, i've had that trouble too in the past where thinkfan did not start.
But, here is my thinkfan -n output:

sudo thinkfan -n

WARNING: Using default fan control in /proc/acpi/ibm/fan.

sleeptime=5, tmax=56, last_tmax=56, biased_tmax=56 -> fan="level 2"

So, the fan is at level 2, and I get no air movement or sounds.

To get the temp to 100C, I honestly just let it sit there for a while on my desk while I was working on something else. I was in gnome-shell with probably chromium, evince, and thats probably it open. I do not have bumblebee enabled and am running on the discrete graphics chip (I will save that for another day).
Thanks again

laxsu19 · 2012-05-31 15:45:46

Well my warranty repair box just came in. I'll send this off on its way, we'll see what happens.

jakobcreutzfeldt · 2012-05-31 15:48:09

Trilby wrote:

That's a high speed for acpi to report - I suspect it is the harware's max speed (you should be able to check this). You'd HEAR that running.

65535 is the maximum value an unsigned short int can take.

Trilby · 2012-05-31 15:57:27

Ah, good catch jakob, I should have seen that. Nonetheless it is quite high and likely means that acpi is "trying" to increase the fan speed.

Arch Linux

#1 2012-05-30 14:13:46

Thinkpad T420s - Fan not running, at all

#2 2012-05-30 14:24:29

Re: Thinkpad T420s - Fan not running, at all

#3 2012-05-30 15:24:59

Re: Thinkpad T420s - Fan not running, at all

#4 2012-05-30 17:31:10

Re: Thinkpad T420s - Fan not running, at all

#5 2012-05-31 14:54:14

Re: Thinkpad T420s - Fan not running, at all

#6 2012-05-31 15:45:46

Re: Thinkpad T420s - Fan not running, at all

#7 2012-05-31 15:48:09

Re: Thinkpad T420s - Fan not running, at all

#8 2012-05-31 15:57:27

Re: Thinkpad T420s - Fan not running, at all

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