bjoernvold.com

Intel has this cpu firmware that traditionally is updated via Bios. The linux kernel has had a way of updating the firmware with microcode so that Linux users do not have to do a BIOS update.

This has been a convenient solution.

As of kernel 3.17.2 and LTS 3.14.21-2; the kernel will not automatically load these microcodes anymore.

If you want that; you have to modify your Grub, Gummiboot,Syslinux or ELILO.

As an Arch user I have had the pleasure, but most distros will probably fix this for you.
From the Arch wiki:

The microcode data file contains the latest microcode definitions for all Intel processors. Intel releases microcode updates to correct processor behavior as documented in the respective processor specification updates. While the regular approach to getting this microcode update is via a BIOS upgrade, Intel realizes that this can be an administrative hassle. The Linux operating system and VMware ESX products have a mechanism to update the microcode after booting. For example, this file will be used by the operating system mechanism if the file is placed in the /etc/firmware directory of the Linux system.

AMD microcode will still be autoloaded via linux-firmware, that is part of the kernel.

What puzzles me is the why?

Why would the kernel developers stop auto implementing Intels firmware? As far as I know only Intel and maybe Microsoft have access to that code so it is not open source (not 100% sure about this - but I think so).

Why does the kernel continue to implement AMD microcode?

Let the conspiracy theories begin!

No conspiracy theory that I can find, just as close as I can find to a why or two. It appears to boil down (obviously) to something in Intel's release of the microcode.dat file. What I'm not finding, is that something. It also has something to do with the fact that it is no longer a module, and mostly (but not solely) affects Haswell CPUs.

http://www.linuxquestions.org/questions ... 175433777/

More about the Haswell CPUs: http://comments.gmane.org/gmane.linux.arch.devel/21298

and:

Intel is not even shipping it anymore in
the microcode bundle for whatever undisclosed reason.

https://bugs.debian.org/cgi-bin/bugrepo ... bug=699412

Good links there - thanks.

Intel still releases its microcode data as that microcode.dat file which is not compatible with the kernel update driver

This indicates that those Intel dat files are open.

The Intel files need to be "translated" for the kernel (Intel should have provided this IMO) while AMD delivers .tar bals that can be directly installed.

I guess this is the motivation for Arch to "demonstrate" that difference.

Hopefully we'll be seeing just that. I need to update on this subject though. Work, work, work these days...

I will get to it though.