Re: Modify Thermal trip points, modern kernel acpi /sys/class/thermal/thermal_zone0/
On Wed, 30 May 2012 13:37:35 +0800, Bob wrote:
> Hi on my laptop (ASUS EeePC 1215b) an AMD E-450 based system the current
> open source drivers in Wheezy don't manage power very well so the system
> overheats & the battery doesn't last long. 
You mean the heat problematic comes exclusively from the GPU? :-?
I would also check that cpufreqd is propelry loaded and set with a low
power consuming profile. Also, if your netbook has an option to switch to
a lower VGA mode it can be also something worth to try.
> I've got squeeze running quite nicely with kernel, fglrx & their
> dependencies coming from backports, but even then if you tax both cores
> the CPU temperature climes quite quickly.
Mmm... is also hot with ATI closed-source driver?
> What I'd like to do is lower the temperature at which active cooling
Changing that values manually can be a risk as this is usually set by the
BIOS or the VGA card.
> acpi -V
> Battery 0: Unknown, 99%
> Battery 0: design capacity 5200 mAh, last full capacity 5360 mAh = 100%
> Adapter 0: on-line
> Thermal 0: ok, 75.0 degrees C
> Thermal 0: trip point 0 switches to mode critical at temperature 95.0 degrees C
> Thermal 0: trip point 1 switches to mode passive at temperature 120.0 degrees C
> Cooling 0: LCD 0 of 10
> Cooling 1: Processor 0 of 10
> Cooling 2: Processor 0 of 10
Those "thermal" trip point values seems to be wrong (passive should be
reached before critical, that is, when the computer is at a lower
Install and configure "sensors" (or another power-management tool for eeepc)
and see what it says, to compare both results.
> is "mode critical" the temperature above which the fan starts or at
> which the system shuts down?
"Trip point" (as its name suggests) indicates a state when an event is
reached and action takes place, so I'm more inclined for the former.
> Also shouldn't "mode passive" be around 50 assuming it's the temperature
> below which the fan turns off to rely on passive cooling?
Yup, I also noticed that. It seems wrong.
> How do I modify these numbers now the /proc/acpi thermal stuff is
I wouldn't tweak these values manually. Maybe you can install a tool that
make your fan to be always "on" but a hot computer usually means something is
wrong: either you have not loaded the proper modules to control power
management or there's a bug in some place (drivers, BIOS...).