[RFC] Patch to enable temperature ceiling in powerd

[Daniel Eischen]

On Wed, 20 Feb 2008, Johannes Dieterich wrote:

> First, thanks for your reply!
>
> Kevin Oberman wrote:
>>> Date: Wed, 20 Feb 2008 22:10:41 +0100
>>> From: Johannes Dieterich <dieterich.joh at googlemail.com>
>>> Sender: owner-freebsd-acpi at freebsd.org
>>>
>>> Alexandre "Sunny" Kovalenko wrote:
>>>> On Sun, 2008-02-17 at 14:40 +0100, Johannes Dieterich wrote:
>>>>> Hi,
>>>>> some not so nice news:
>>>>>
>>>>> That still holds true. Unfortunately portupgrade gcc overheats it again.
>>>> You might want to do
>>>>
>>>> sysctl hw.acpi.thermal.user_override=1
>>>> sysctl hw.acpi.thermal.tz1._PSV=85C
>>>>
>>>> and see if this gets you through the gcc compilation.
>>> for a long long time it looked very good. But then it again overheated.I
>>> might want to stress again that it happened out of a sudden. sysctl
>>> dev.cpu reports 83-87 degrees for a long time and then it SUDDENLY shuts
>>> down saying it is over 127 degrees. The workload between those two data
>>> points has not changed.
>>
>> This is sounding like a hardware problem.
>>
>> On almost all modern systems, the CPU temperature is read from a single
>> junction on the silicon of the CPU. If it makes sudden, inexplicable
>> jumps, this implies that either the junction on the chip or the support
>> hardware on the mobo (this is analog stuff) is misbehaving.
>>
>> It is possible that something is causing BIOS to handle the values
>> incorrectly, but that would seem very unlikely to me.
>
> In general, I am willing to believe these things. There is a but though.
> The problem appeared when upgrading from 6.2 to 7.0. OK, hardware breaks
> and coincidences happen. But I tested later with an openSUSE and a
> Knoppix Live CD (OK, JUST a LiveCD) and a stress test and it never went
> over 79 degrees. But it reproducibly happens with FreeBSD 7.0 and also
> there just under load (which puts the temperature anyway to 85 degrees).
> I do lack an install of a Linux to test these issues there because the
> notebook is my productive system at the moment.

I also have to think that maybe this isn't a hardware issue.
I'm having similar problems with an Intel STL2 Tupelo motherboard
after upgrading to 7.0.  Only under load does the temperature
shoot up, but I know the chip isn't getting hot and the fan
is running - I've felt around in there and nothing was even
close to the 117+C it was sensing.

-- 
DE