[patch] enhance powerd(8) to handle max temperature

[Nate Lawson]

M. Warner Losh wrote:
> In message: <46AE8F78.1060203 at root.org>
>             Nate Lawson <nate at root.org> writes:
> : Hajimu UMEMOTO wrote:
> : >>>>>> On Mon, 30 Jul 2007 23:31:33 +0200
> : >>>>>> Pietro Cerutti <gahr at gahr.ch> said:
> : > gahr> My patch is really just a first draft that I wrote in order to have
> : > gahr> feedbacks on the general idea to implement a temperature controlling
> : > gahr> system inside powerd, and doesn't implement hysteresis as you noted, and
> : > gahr> your feedback is that it's not a good idea, which I respect.
> : > 
> : > It is rather backward, IMHO.  I did implement a passive cooling
> : > feature as an enhancement of powerd(8) like you did, during initial
> : > phases.  Then, I implemented it in our kernel as a result.
> : 
> : I'll take a look at your patch.  Umemoto-san is right in that you really
> : want the kernel to control cooling.  What happens if powerd dies/hangs
> : and your system burns up?  Passive cooling is often a last resort to
> : keep the system from overheating.
> 
> I keep getting the system shutting down on my HP by FreeBSD because
> the temperature exceeds the _CRT value.  Maybe there's something wrong
> with my values, since it happens a lot:
> 
> hw.acpi.thermal.min_runtime: 0
> hw.acpi.thermal.polling_rate: 10
> hw.acpi.thermal.user_override: 0
> hw.acpi.thermal.tz0.temperature: 0.0C
> hw.acpi.thermal.tz0.active: -1
> hw.acpi.thermal.tz0.passive_cooling: 1
> hw.acpi.thermal.tz0.thermal_flags: 0
> hw.acpi.thermal.tz0._PSV: 90.0C
> hw.acpi.thermal.tz0._HOT: -1
> hw.acpi.thermal.tz0._CRT: 94.0C
> hw.acpi.thermal.tz0._ACx: 40.0C -1 -1 -1 -1 -1 -1 -1 -1 -1
> 
> Note: temperature is always 0.0C.
> 
> What can I do to help my situation, if I really want the kernel doing
> the cooling?

Your embedded controller is timing out.  Thus you're getting a bogus
value for _TMP.

Those settings for _CRT appear correct.  It's the "measured" temperature
that is wrong.

-Nate