Ubuntu
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  1. Bug #964480
  2. Comment #8

Comment 8 for bug 964480

Revision history for this message
In , nevermaker (nevermaker-linux-kernel-bugs) wrote :

Created attachment 72744
output of dmidecode on my machine.

My MacBook Air gets quite hot to the touch during minor usage (i.e. machine sitting untouched with browser and terminals open). The fan should really be starting up before the machine becomes uncomfortable to touch, but for some reason the fan is not triggered.

For comparison against the older kernel version, I monitored the temperatures using GKrellM:

Kernel version 3.2:
- CPU temperatures start at around 50 C, and rise to 60 under load.
- The fan does not kick in until high load raises the temperature.
- Fan is able to cool the machine back down to 60, and then the fan shuts down.

Kernel version 3.3:
- CPU temperatures climb QUICKLY until 75 while the machine is completely idle.
- Fan kicks in around 75 and cools the cpu down to 70 or so.
- The temps don't decrease below 70ish, so the fan never comes down from high speed.
- Under minor usage (browser, terminal, and gkrellm) cpu temps are rising faster than the fan can compensate. temp is above 80, but the fan is maxed out already.
- This is evidence that the fan at its highest speed is not enough to cool the computer down.

Kernel version from Ubuntu PPA, http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.3-precise/