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Re: therm_adt746x



On Sun, 2004-09-12 at 00:05, Florian Reitmeir wrote:

> On Tue, 31 Aug 2004, Chris Anderson wrote:
> 
> > > i use my iBook G4 since dec/03 and never used the module "therm_adt746x". Now
> > > sometimes people post, that the module is important, and write things like,
> > > 
> > > "not using the module may damage your hardware"
> > > 
> > > is that true?

Well I ran a default debian sarge install for a couple of weeks with the
machine on pretty much all the time and didn't have the module load. At
this stage there doesn't seem to be any hardware problems at all. When I
do load the module the fan comes on consistently more under Linux than
it does under Mac OS X. (In fact I _don't_ remember it coming on at all
under Mac OS X whereas I _do_ notice it coming on a _lot_ under Linux
with the module loaded).

> > Yes, since without that module your ibook will never use any of its
> > built in fans. Thus heat will build up and potentially cause hardware
> > failure.
> 
> Thats not true, my Fans work just fine, on heavy load, even without the
> module. The module itself claims only to lower the max. temp. so the fans run
> more often.

That the fans _will_ kick in when things get _hot_ is nice to know :-).

> The question remains, is this module a must have, or an add on?

Well, when I 'modprobe therm_adt746x' this is what appears in
/var/log/messages :-

Sep 12 00:08:12 localhost kernel: adt746x: Thermostat bus: 1, address: 
0x2e, limit_adjust: 0, fan_speed: -1
Sep 12 00:08:12 localhost kernel: adt746x: ADT7467 initializing
Sep 12 00:08:12 localhost kernel: adt746x: Lowering max temperatures
from 69, 92, 101 to 70, 50, 70 (°C)
Sep 12 00:08:12 localhost kernel: adt746x: Setting speed to: 0 for CPU
fan.
Sep 12 00:08:13 localhost hal.hotplug[26404]: Dont know how to wait for
i2c at /devices/uni-n-i2c/i2c-5/5-002e; sleeping 1000 ms
Sep 12 00:08:13 localhost hal.hotplug[26403]: Dont know how to wait for
of_platform at /devices/temperatures; sleeping 1000 ms
Sep 12 00:08:14 localhost kernel: adt746x: Setting speed to: 128 for CPU
fan.

Pretty much the fan kicks in straight away because it seems the
temperature is above 50C. When I 'rmmod therm_adt746x' then the
following appears in /var/log/messages :-

Sep 12 00:08:26 localhost kernel: adt746x: Putting max temperatures back
from 70, 50, 70, to 69, 92, 101, (°C)
Sep 12 00:08:26 localhost kernel: adt746x: Setting speed to: automatic
for CPU fan.

I suppose I have two questions.

(a) What do the series of temps represent (i.e. are they related to
certain fan speeds, cpu temps, system temps etc.)

(b) How can I get sensors working so I can find out what the current
temp is (stock sarge kernel - 2.6.8powerpc)

>From this I then hope to tweak the module fan speeds so that it kicks in
at higher temp than default allowing my battery to last for longer.

Michael Hunt



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