[GTALUG] Ryzen 3000 CPUs vs Linux

[D. Hugh Redelmeier]

These barnd new chips look really attractive.  Unfortunately, most resent 
Linux distros fail to boot on them.  Debian 10 is apparently OK.

The central problem is (another!) bug in AMD's implementation of the 
rdrand instruction.

This shows up because systemd 240 and later tries to actually use rdrand.  
systemd 243 has code that works around the AMD bug.

Apparently Fedora 30, ubuntu 19.04, and other systemd-using distros' 
installation media have systemd versions that are affected.

I first saw this on phoronix:
  <https://www.phoronix.com/scan.php?page=article&item=ryzen-3700x-3900x-linux>
but I think that this is a better writeup:
  <https://linuxreviews.org/AMD_Ryzen_3000_series_CPUs_can%27t_do_Random_on_boot_causing_Boot_Failure_on_newer_Linux_distributions>

Note: I have no first-hand experience so I cannot vouch for the details.