The new thermal managemeny sysfs class that was just merged into acpi-test, especially when dealing with temperature measurement and fan control, has a lot of common ground with the hwmon interface. However, the ACPI model for thermal cooling devices (fans, etc) and thermal zones (temp sensors) as currently implemented in the sysfs class appears at first glance to be a lot more simplified than what is available through the hwmon sysfs ABI (for a lack of a better term to describe the sysfs attribute specifications). And the two sysfs ABIs are incompatible. The ACPI one uses low-precision units, (temperature in 10^0 degrees Celcius), while the hwmon ABI uses medium precision units (10^-3 degrees Celcius), for example. There is also no tachometer feedback for fans, etc. Missing functionality in the new thermal class are apparently mainly related to the idea of hardware-based temperature limits and alarms, plus any non-trivial fan control schemes (many chips, and in case of thinkpad-acpi, EC firmware, have auto-cruise modes, some have more than one automatic fan control scheme, etc). If I am wrong about this, please correct me. IMHO, we can probably do better than two incompatible sysfs ABIs for what ammounts to the same functionality for many userspace applications (i.e. thermal monitor apps, and fan control and monitoring apps). And it would be really neat if the new thermal management stuff could just plug into the already available temperature sensors and fan controllers that follow the hwmon sysfs ABI. Any thoughs on this? -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
