Acer Laptop overheating with ACPI error that I don't understand.

[Alexandre "Sunny" Kovalenko]

On Tue, 2009-07-14 at 18:54 -0500, Edwin L. Culp W. wrote:
> I am having overheating problems with my Acer Aspire laptop.
> # uname -a
> FreeBSD ed.local.net.mx 8.0-BETA1 FreeBSD 8.0-BETA1 #256: Thu Jul  9
> 07:05:20 CDT 2009     root at ed.local.net.mx:/usr/obj/usr/src/sys/ENCONTACTO
> i386
> 
> I've been having this problem for several months and compensating by
> reducing dev.cpu.0.freq from 1900 to 1200 and 800 in warm offices.
> 
> The errors I'm seeing in the log files are:
> 
> +acpi_ec0: EcRead: failed waiting to get data
> +ACPI Exception: AE_NO_HARDWARE_RESPONSE, Returned by Handler for
> [EmbeddedControl] 20090521 evregion-531
> +ACPI Error (psparse-0633): Method parse/execution failed [\\_TZ_.THRM._TMP]
> (Node 0xc4e75960), AE_NO_HARDWARE_RESPONSE
> 
> I'm afraid that I don't understand them.
This means that FreeBSD tried to execute method, provided by your ACPI
BIOS, that is supposed to return current temperature, and execution did
not complete within certain time limit (I do not have -CURRENT system
handy to tell you what the limit is). I would recommend taking this to
acpi@ mailing list, unless it used to work under -STABLE and ceased
under -CURRENT.

Output of 'sysctl hw.acpi' should give you a clue, especially
temperature field.

Next steps could be:
-- see if there is BIOS update for your hardware.
-- boot some kind of live CD of the system, you are familiar with, and
check temperature value(s). They should be reasonable and should change
with the load.
-- If your BIOS is up-to-date and nothing gives you reasonable
temperature readout, it might be hardware problem. Alternatively, it
might be that your ACPI BIOS was never designed to work with anything
but Windows -- I have seen few of those in the past. If latter is the
case, disassembling your ASL (see handbook for instructions) and reading
through it with ACPI spec at hand, starting with the _TMP method above,
might get you somewhere. Thermal section of the ACPI spec is
self-sufficient, well-written and has documented example. 
-- ask on acpi@ whether there is tunable and/or hack which can extend
timeout value -- it could be that whatever hardware your ASL is talking
to just takes its own time to respond..

HTH,
-- 
Alexandre Kovalenko (Олександр Коваленко)