Re: Ryzen public erratas

On Mon, 18 Jun 2018 22:44:13 -0700
Eitan Adler <lists_at_eitanadler.com> wrote:

> On 13 June 2018 at 04:16, Eitan Adler <lists_at_eitanadler.com> wrote:
> > On 13 June 2018 at 03:35, Konstantin Belousov <kostikbel_at_gmail.com> wrote:  
> >> Today I noted that AMD published the public errata document for Ryzens,
> >> https://developer.amd.com/wp-content/resources/55449_1.12.pdf
> >>
> >> Some of the issues listed there looks quite relevant to the potential
> >> hangs that some people still experience with the machines.  I wrote
> >> a script which should apply the recommended workarounds to the erratas
> >> that I find interesting.
> >>
> >> To run it, kldload cpuctl, then apply the latest firmware update to your
> >> CPU, then run the following shell script.  Comments indicate the errata
> >> number for the workarounds.
> >>
> >> Please report the results.  If the script helps, I will code the kernel
> >> change to apply the workarounds.
> >>
> >> #!/bin/sh
> >>
> >> # Enable workarounds for erratas listed in
> >> # https://developer.amd.com/wp-content/resources/55449_1.12.pdf
> >>
> >> # 1057, 1109
> >> sysctl machdep.idle_mwait=0
> >> sysctl machdep.idle=hlt  
> >
> >
> > Is this needed if it was previously machdep.idle: acpi ?  
> 
> This might explain why I've never seen the lockup issues mentioned by
> other people. What would cause my machine to differ from others?
> 

I had sysctl machdep.idle_mwait=1 and machdep.idle=acpi before
applying the shell script.  I had multiple lockups every week,
sometimes multiple lockups per day.

With the idle settings from the script it still locks up, but
not as often.

I suspect I also need to update the CPU firmware, although I
expect that the new BIOS version I installed last week would
have done that already.

-- 
Gary Jennejohn