28 lines · plain
1============2Introduction3============4 5The firmware API enables kernel code to request files required6for functionality from userspace, the uses vary:7 8* Microcode for CPU errata9* Device driver firmware, required to be loaded onto device10 microcontrollers11* Device driver information data (calibration data, EEPROM overrides),12 some of which can be completely optional.13 14Types of firmware requests15==========================16 17There are two types of calls:18 19* Synchronous20* Asynchronous21 22Which one you use vary depending on your requirements, the rule of thumb23however is you should strive to use the asynchronous APIs unless you also24are already using asynchronous initialization mechanisms which will not25stall or delay boot. Even if loading firmware does not take a lot of time26processing firmware might, and this can still delay boot or initialization,27as such mechanisms such as asynchronous probe can help supplement drivers.28