amd64-microcode for Debian -------------------------- Introduction: AMD AMD64 processors are capable of field-upgrading their control program (microcode). These microcode updates correct processor errata, and are often important for safe, correct system operation. While most of the microcode updates fix problems that happen extremely rarely, there are enough updates fixing issues that would cause system lockup, memory corruption, or unpredictable system behavior, to warrant taking it seriously. Microcode updates are ephemeral: they will be lost after a processor hard reset or after the processor is powered off. They must be reapplied at every boot and after the system wakes up from suspend to RAM or disk. Updating the processor microcode is the responsibility of the system firmware (BIOS or EFI). However, not all vendors will release timely updates for their firmware when AMD releases updated microcode, and most users don't update their system firmware in a timely fashion (or at all) anyway. The end result is that, unless some other method of distributing microcode updates is in place, the processor in many systems will be running with outdated microcode, increasing the chances of incorrect system operation. Debian can apply microcode updates to the system processors during the operating system boot. The following configurations are supported for the microcode driver: 1. When an initramfs image is used (Debian default), both modular and built-in configs for the microcode driver will work, and microcode will be updated by the initramfs. You must run "update-initramfs -u" when new microcode is manually installed to /lib/firmware (this will be done automatically when new microcode is installed by a package upgrade). 2. When an initramfs image is not used, only the modular microcode driver is supported. If it doesn't autoload by itself in your kernel version, you should add it to /etc/modules. You must install either the kmod or module-init-tools package, and the root filesystem with /lib/firmware must be available when the modules are loaded. -- Henrique de Moraes Holschuh , 2012-07-09