olivetalks

I’m running Fedora 9 on my laptop. Everything works great but the default installation doesn’t deal properly with thermal management. The OS doesn’t lower the CPU clock when the processor is heating up too much. Normally it doesn’t matter much unless you run some software which will fully utilize the CPU for an extended period. For example when you compile a big software project. Because the OS doesn’t activate the thermal throttling the CPU keeps running at full speed and after some time the system gets really hot. Beside the obvious danger of getting burned – if you keep the laptop on your lap – there is a chance of damaging the laptop’s components.

In my case the victim was the battery. First its capacity got drastically reduced to about 30% of the original capacity and then it completely refused to work. Good that batteries can be replaced

All this sounds pretty bad. Fortunately there is an easy way to prevent this problem.

Fedora 9 includes a tool called cpuspeed which can react to increasing system temperature and throttle down the CPU. cpuspeed is included in the default installation but it needs to be configured before it can prevent thermal damage to the laptop. The configuration is quite simple:

1. Download cpuspeed configuration file and save it as /etc/sysconfig/cpuspeed.
2. Adjust the saved file to match your system – especially options MAX_SPEED and MIN_SPEED.
3. Make sure cpuspeed daemon is configured to start automatically when system boots: /sbin/chkconfig cpuspeed on
4. Restart cpuspeed daemon: service cpuspeed restart

That’s it – I’ve been running my laptop with this configuration for a few months already and the CPU gets throttled down whenever the system gets hot.