ThinkPad laptops include a proprietary interface called SMAPI BIOS (System Management Application Program Interface) which provides some hardware control functionality that is not accessible by other means. tp_smapi is highly recommended if you're using a ThinkPad laptop. Not all functions are available on all models; for detailed status, see: http://thinkwiki.org/wiki/tp_smapi WARNING: This driver uses undocumented features and direct hardware access. It thus cannot be guaranteed to work, and may cause arbitrary damage (especially on models it wasn't tested on).