Re: Erratic fan speed and little control kernel 4.2

From: Pali RohÃr
Date: Fri Dec 04 2015 - 04:18:22 EST


Hi Peter!

On Thursday 03 December 2015 20:26:51 Peter Saunderson wrote:
> Erratic fan speed and little control kernel 4.2
>
> After upgrading to kernel 4.2 my CPU fan started speeding and slowing
> without good reason even when the PC is idle.
>
> To stop erratic fan speed - reboot sometimes works.
>
> This bug has been bisected to commit
> f989e55452c74b4f7b22c889b8ec9f1192aaeec4

There is very similar (or same) problem on desktop Dell Studio XPS 8100.
See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121

In your long email is missing one important information: DMI information
about your machine. Can you run dmidecode and send output?

You were able to bisect problematic commit, are you able to do some
additional test and debug root of this issue?

In my opinion problem is in some SMM call, but without commenting code
which calling it, step by step and testing is not possible to decide...

--
Pali RohÃr
pali.rohar@xxxxxxxxx
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