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2019-07-20 - 18:12
2007-08-26 22:00 Age: 12 Years

The OSADL Upstream Submission Program in action

By: Carsten Emde

Two more sensor chip drivers made it into Mainline Linux.

Fan-regulated chip temperature

Not only when Linux 2.6.22 was released but also when Linux 2.6.23-rc1 appeared, OSADL was (at least a very small) part of it: Both the MX6650 sensor chip driver that is now integrated in the released kernel version 2.6.22 and the LM93 sensor chip driver that is included in the release candidate for 2.6.23 have been prepared for upstream submission in an OSADL project.

Why is a sensor chip driver relevant for the automation industry? Sensor chips provide continuous monitoring of a system's vital data such as temperatures, fan speed and voltages. In combination with appropriate monitoring software such as Munin and Nagios, early signs of a system failure can be signaled to prevent major damage. Even the correct function of a fan speed regulator can be assessed at a glance (see Figure): The fan speed (below) closely follows the chip temperature (above) and, thus, takes care that the processor works at nearly constant temperature - whenever possible.. Wednesday evening, however, someone decided to recompile an entire project with the -j4 make option. This produced so much heat that the fan was unable to regulate the temperature, but the maximum chip temperature was, by far, still not reached.

Have you already defined or will you ever define

CONFIG_SENSORS_MAX6650=m

or

CONFIG_SENSORS_LM93=m

in your .config file? If so, we are glad that our work has helped to make the Linux kernel a bit more versatile.

Thanks to Hans-Jürgen Koch for working on the driver and to Jean Delvare and Mark M. Hoffman for maintaining the lm_sensors project. Click here to inspect the list archive or to subscribe to the mailing list.