[ltp] wireless switch: is off really off?

[Arno Trautmann]

Hi,

until a few days ago, I didn’t manage to get my W-LAN running, so I 
always disabled it by turning the swith to ”off“. But the machine was 
very warm underneath the fingerprint-reader. (a X61s)
Then I finally managed to get W-LAN, and found this on thinkwiki:

--
If you need Wi-Fi, you can also reduce power consumption (at the price 
of performances) by activating the power saving modes:

iwpriv eth1 set_power 5

For drivers using the new Wi-Fi kernel framework (mac80211/cfg80211), 
the canonical way to do this is now:

for i in /sys/bus/pci/devices/*/power_level ; do echo 5 > $i ; done
--

Using this, the machine is much cooler, /with/ W-LAN enabled and active. 
So what caused the heating? Was it the w-lan card anyhow /not/ disabled 
by the switch? Or does the last code line change anything else than w-lan?
I’m very happy now, having temperatures of about 40°C instead of nearly 
50°C—but I would like to understand, why…

Thanks,
Arno