At Linux level, a more sophisticated protection mechanism is implemented. Please refer to the following sections for more details.
=====XELK 12.x.y series=====Practically speaking, for [[Axel_Embedded_Linux_Kit_(XELK)#XELK_software_components|XELK 2.x.y series]] this mechanism makes use of two different thresholds, denoted as <code>trip_point0</code> (also known as ''passive threshold'') and <code>trip_point1</code>(also known as ''critical threshold''. When Tj reaches <code>trip_point0</code>, Linux kernel scales down processor frequency:
<pre>
System is too hot. GPU3D will work at 1/64 clock.
thermal thermal_zone0: critical temperature reached(100 C),shutting down
</pre>
Trip point thresholds can be accessed via <code>sysfs</code> interface from user space.
By default, temperature thresholds are set up as follows:*<code>trip_point0</code>: 85°C*<code>trip_point1</code>: 100°C. Trip point thresholds can be accessed via <code>sysfs</code> interface from user space. The following example shows how to read the values of the trip points: