Lan Barnes wrote:
On Sat, April 14, 2007 2:05 pm, DJA wrote:
Lan Barnes wrote:
:'-(
It'll run idle overnight with no problems, but when I load the CPU (top
says 30%), it goes from 38 C to 68 C in about 4 minutes.
I'm taking it back and making the case that the original diagnosis
charge
should still be in force.
Everyone keeps assuming that the problem is related to hardware. It may
very well not be. Fan and Processor speed are controlled both at the
BIOS level, and by ACPI. Someone mentioned Sensors - Sensors cannot
write, it can only read temp and fan settings, and in fact is known to
interfere with ACPI (which can and /does/ manage fan/CPU/temp settings)
on some laptops.
I don't remember if you have Windows running on the laptop, but if you
do, then a sure way to see if it's hardware vs. firmware/software, is to
see if it overheats in Windows. In fact you may have to install Windows
just to get a reliable diagnosis. Looking at hardware only is _not_
going to give a definitive answer unless something is obviously broken.
Keep in mind that laptop manufactures' BIOS writers seldom properly
follow ACPI and ACPICA (Intel) specs, so many models don't work as
expected when it comes to fan/CPU/heat management. In Linux, it's the
job of ACPI to compensate. It's a very tough whack-a-mole type problem.
But it's getting better fast.
There are ways to read your laptop's temp trip points and their
associated fan speeds and CPU throttle points. Sometimes just upgrading
to a newer kernel can fix the problem. Sometimes just upgrading to a
newer kernel causes a problem.
I've found it educational and helpful to follow the ACPI4Linux mailing
list as well as the one specific to ACPI for my laptop. You may want to
do the same.
I don't recall what brand of laptop you have, but if you can identify
the maker of its motherboard, you may find there is an ACPI kernel
module specific to it. For instance, there are for Sony, IBM, Asus, and
I think MSI and Toshiba. Do a search in Dmesg or the Syslog and look for
any strings containing "ACPI".
Wow! That makes sense. I just got it back after a second day of
diagnostics. They DID run it under windoze for that and it DID complete a
night of trouble-free CPU 100% running. They chacked the temp with an
external thermometer (the laser kind -- gotta get one of those). All was
well.
Result -- No HW probs that they can see.
I'm sitting here seeing it say it's at 30 C. If I push it, I'm betting
it'll say 68 C. If it doesn't shut itself off, and if I believe it's
really 30 - 40, do I care? That's a real question.
And what's shutting it off when it gets hot? I think you might have
mentioned something in the logs about overheating. Maybe the kernel is
shutting it down because it's reading the wrong temp.
Karl
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