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Re: Fan control ?


I just signed up to debian-powerpc, and noticed Niels S. Eliasen's question from September 7th. I was able to get some power management and sensors working on my g4 powerbook (12" 1.33GHz PowerBook6,4).

It is now serving as a webserver, NAT firewall, and wireless access point. (hostapd works with the nl80211 drivers in master mode, but required updating to kernel 2.6.30 from backports and hostapd 0.6.9 from testing.)

Try the following to get a reading of the temperature and fan speed (I've included the output on my machine as an example):

$ cat /sys/devices/temperatures/*temp*
$ cat /sys/devices/temperatures/*fan*
64 (4770 rpm)
64 (0 rpm)

The temperatures are in Celsius, with sensor?_location (in the same directory) giving "CPU TOPSIDE" for the first and "GPU ON DIE" for the second. I installed powernowd to get some control over the cpu scaling, but I don't know whether that will work on a tibook.

The best way I was able to manage some control over the fan was to do:

echo 2 >> /sys/devices/temperatures/limit_adjust

which adds 2 degrees to the temperature at which the fan steps up and down, keeping it at low speed slightly longer. Setting it to -4 would have the fan on most of the time, while 4 would mean it wouldn't step up until the temperature got much higher. I don't know of any way to change the exact values; limit_adjust applies to all of the built-in values, and the only way I can figure them out is to watch what temperature causes the fan to step up and down.

Hope this helps!

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