On 2019-01-21 Bill Reid wrote:

I am running Ryzen 2nd generation with Ubuntu 18.10. The first CPU I had Ryzen 5 2400 started causing reboots after a couple of months. Waiting for replacement. Currently running Ryzen 3 2200.

Outside of the first CPU failing no other problems.

On 2019-01-20 6:59 p.m., Trevor Cordes wrote:

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Is anyone here using Ryzen (1 or 2, or derivatives) with Linux? (ECC irrelevant, fyi.)

Brad & my Ryzen build yielded interesting results. Thanks for your reply, and I hope to hear from anyone else with Ryzen + Linux.

We had it freeze within 5 hours of first booting. Apparently there's a nasty chip "bug". If your reboots were more like freezes (or even if not), you might have just been hitting this bug. A CPU change will not fix it. It's a fundamental flaw. Doesn't affect Windows, just Linux and (most?) BSDs. MS probably got tips from AMD on mitigation.

https://bugzilla.kernel.org/show_bug.cgi?id=196683

TLDR; easy fix is in the BIOS find the "CPU idle power" or similar and change it to "typical" or "common" instead of AUTO. Also add idle=nomwait to kernel boot parms (may be superfluous after bios tweak?). As nearly everyone on the bz thread reports, these tweaks instantly solve the problem.

More info: problem appears to be with C6 power state of CPU and when the box goes too idle, too many cores go into too low a voltage and a) some PS's get confused possibly, and b) the cpu, mobo and ps can't react quick enough when a core suddenly wakes up from C6 to full-bore mode. The power starve crashes a core, or 6.

BIOS tweak tells the CPU to not go into the deepest states at all, instead keeping a more even power draw. However, lesser states should still function so the tweak shouldn't cost more than a few watts (some people claim 8W at idle) wastage (and none if you aren't idle very much).

I'm pretty flabbergasted that this issue isn't further widespread, and isn't really being addressed by AMD because it doesn't affect Windows. It's 1.5+ years old and can affect all Zen-cored CPUs, 1st and 2nd gen. Kernel guys don't seem too excited about it, probably none of them are using Ryzen yet.

On the bright side, ECC does indeed seem to work perfectly with the new setup! Yay.

On 2019-01-22 Bill Reid wrote:

No, my bug did not seem to be that problem. It would not freeze but just reboot. Oddly it got worst as time when on. Initial I could boot into Ubuntu, then only to grub, then eventually it would reboot as grub was loading.

That's a weird, and rather scary, CPU failure you had.

If you never saw the "idle freeze" bug with your setup, that's very interesting. I wonder what makes some systems susceptible.

Can you post your hardware specs (each component P/N, etc)? And can you check the +12V amp min rating of your PS? Apparently having a PS that says 0A@+12V can help alleviate this bug somewhat, though many people with that are still seeing the bug.

Strange but I've yet to see someone complain of the bug on the Ryzen 3. It's always 5 or 7, but it could be that most linux-ers are more likely to go for the better chips. So I'm curious what you'll see once you get a working 2400 chip back in there.

Also, can you d/l and run: https://github.com/r4m0n/ZenStates-Linux/blob/master/zenstates.py

zenstates.py -l

and post the 2 C6 lines: C6 State - Package - Disabled C6 State - Core - Enabled

I'm curious to see if something in your setup is already setting things as shown above. That's what our "fixed" working setup is showing. Normally both would be Enabled with a default "broken" setup.