Recently my notebook has started shutting down with these messages in the logs: ACPI: Critical trip point Critical temperature reached (128 C), shutting down. But it didn't seem hot at all to me, so I wrote a script to cat /proc/acpi/thermal_zone/THRM/temperature once a second and eventually caught this (but no shutdown): temperature: 47 C temperature: 47 C temperature: 128 C temperature: 48 C temperature: 47 C Google found several people reporting problems like mine after installing lm-sensors, and when I looked at the list of loaded modules I found k8temp and hwmon there. Then I realized my problems had started after installing a 2.6.19 kernel that had the new k8temp driver. So, could ACPI and the k8temp driver be at odds?