From: "Pali Rohár" <pali.rohar@gmail.com>
To: Thorsten Leemhuis <fedora@leemhuis.info>
Cc: "Jan C Peters" <jcpeters89@gmail.com>,
"David Santamaría Rogado" <howl.nsp@gmail.com>,
"Peter Saunderson" <peteasa@gmail.com>,
"Jean Delvare" <jdelvare@suse.com>,
"Guenter Roeck" <linux@roeck-us.net>,
"Tolga Cakir" <cevelnet@gmail.com>,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dell-smm-hwmon: Cache fan_type() calls and use fan_status() for fan detection
Date: Mon, 13 Jun 2016 20:30:14 +0200 [thread overview]
Message-ID: <201606132030.14769@pali> (raw)
In-Reply-To: <b15e8039-f5e4-b373-7a0d-397a92f873b6@leemhuis.info>
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On Monday 30 May 2016 13:45:51 Thorsten Leemhuis wrote:
> Pali Rohár wrote on 27.05.2016 15:21:
> > On Friday 27 May 2016 15:05:54 Thorsten Leemhuis wrote:
> >> Pali Rohár wrote on 27.05.2016 12:45:
> >> So I tried a few things
> >> and came to the conclusion: the problem shows up as soon as
> >> i8k_get_fan_type() (introduced in f989e55452) is called somewhere.
> >
> > So, once kernel call i8k_get_fan_type() function, then fan speed
> > going up/down?
>
> Yes.
>
> > To make sure that this is root of your problem, can you take some
> > older kernel version (where is i8k working fine) and try to
> > patch+call that i8k_get_fan_type() function? To check that
> > something else cannot interference with it...
>
> I just tried with 3.19.8 (had to install a older distro first :-/ ),
> where the problem does not show up (I verified just to be sure). Then
> I applied below patch and voila: the fan speed starts going up/down.
>
> IOW: From what I can see that SMM call that i8k_get_fan_type()
> triggers the problem on my Studio 8000
>
> CU, knurd
>
Thank you for your testing! I believe now we definitely know root of
this problem. It is buggy Dell BIOS/SMM code and we need to avoid
calling I8K_SMM_GET_FAN_TYPE on affected buggy Dell machines.
--
Pali Rohár
pali.rohar@gmail.com
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prev parent reply other threads:[~2016-06-13 18:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-21 14:46 [PATCH] dell-smm-hwmon: Cache fan_type() calls and use fan_status() for fan detection Pali Rohár
2016-05-22 0:19 ` Guenter Roeck
2016-05-22 0:28 ` Pali Rohár
2016-06-13 18:52 ` Pali Rohár
2016-06-14 2:02 ` Guenter Roeck
2016-06-15 8:03 ` Pali Rohár
2016-05-26 15:39 ` Thorsten Leemhuis
2016-05-26 15:51 ` Pali Rohár
2016-05-27 8:00 ` Thorsten Leemhuis
2016-05-27 9:47 ` Pali Rohár
2016-05-27 10:01 ` Thorsten Leemhuis
2016-05-27 10:45 ` Pali Rohár
2016-05-27 13:05 ` Thorsten Leemhuis
2016-05-27 13:21 ` Pali Rohár
2016-05-29 19:27 ` Peter Saunderson
2016-05-30 9:36 ` Pali Rohár
2016-05-30 16:25 ` Peter Saunderson
2016-06-02 13:06 ` Pali Rohár
2016-05-30 11:45 ` Thorsten Leemhuis
2016-06-13 18:30 ` Pali Rohár [this message]
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