devd and/or ACPI not reporting a heat problem

Doug Barton dougb at
Wed Jun 16 07:04:26 UTC 2010


I thought my heat problems were over with this laptop thanks to all the 
great suggestions I've received about powerd, no stepping, etc. (I also 
propped up both the back and the front to make a nice big air pocket.) 
I've always been pretty religious about blowing the dust off the fans 
and heat sinks, but I guess it's been dustier than I thought lately 
because I finally "caught" my laptop doing what it's been doing for the 
last 2 weeks, which is (occasionally) powering down when it was 
unattended; and the problem was heat.

Of course I've been running devd all along, and so I initially ruled out 
the heat problem due to this entry in devd.conf:

# Notify all users before beginning emergency shutdown when we get
# a _CRT or _HOT thermal event and we're going to power down the system
# very soon.
notify 10 {
         match "system"          "ACPI";
         match "subsystem"       "Thermal";
         match "notify"          "0xcc";
         action "logger -p kern.emerg 'WARNING: system temperature too 
high, shutting down soon!'";

I'm not getting any of those notices in the logs, so I was looking other 
places. (I do get other ACPI-related activity from devd, such as the 
notice that it's going on and off AC power.)

So, 2-part question, how can I make sure that devd gets the message, and 
how do I make sure that the notice comes _before_ the BIOS forces the 
system to power off. I.e., I'd like to have some sort of devd notice 
that comes in time to do a clean shutdown, or perhaps some other 
mitigation strategy prior to the BIOS taking over.



	... and that's just a little bit of history repeating.
			-- Propellerheads

	Improve the effectiveness of your Internet presence with
	a domain name makeover!

More information about the freebsd-current mailing list