[lm-sensors] Problem with intel i7: not detected

Jean Delvare khali at linux-fr.org
Thu May 6 18:51:39 CEST 2010

Hi Matthieu,

On Mon, 03 May 2010 21:18:33 +0530, mat wrote:
> I have a Dell Studio 1557 with intel i7, installed with Ubuntu 9.10. As 
> many Dell Studio, it has the problem of overheating, reaching easily 
> temperatures of 80-90, sometimes even shutting down. Now, the fan does 
> not even start...

That would most likely be an ACPI issue. Did you try upgrading your
BIOS to the latest available version already?

> I really have few knowledge of that, but I tried to get better insights 
> running lm-sensors, especially hoping to see whether the fan is 
> recognized...

Fans are almost never supported by lm-sensors on laptops. Except for
integrated CPU sensors (coretemp driver), lm-sensors has to rely on
ACPI for monitoring and that usually means a couple temperature values
being reported and that's it.

You may be able to use vendor-specific kernel modules though, such as
thinkpad_acpi, eeepc-laptop etc. For some Dell laptops, there's the i8k
driver, you should give it a try if you didn't already, but probably
it's for older models.

> Running
> sudo sensors-detect
> I have:
> Trying family `National Semiconductor'...                   Yes
> Found unknown chip with ID 0x8502

We don't know all Super-I/O chips out there. But not all of them
include hardware monitoring features, especially on laptops, so the
above isn't necessarily meaningful. The next investigation step would
be to figure out which chip it is exactly, which means either taking
your laptop apart and looking at all the chips, or asking the vendor.
Not very appealing either way.

> There was a similar post in the list:
> http://www.spinics.net/lists/lm-sensors/msg27726.html
> But I don't really understand what was dealt there, and especially what 
> are the conclusions, especially:
> -whether there is a way to have this chip detected

The chip is already detected. It isn't identified though.

> -whether this is likely to solve my problem of overheating /fan not working

No, rather unlikely. What you want is to disassemble your ACPI tables
(use acpidump) and have ACPI experts look at it. Maybe there's something
wrong in there, that can be fixed by a BIOS update or worked around in
the kernel.

Jean Delvare

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