[coreboot] unstable AMD Fam10h boot

ron minnich rminnich at gmail.com
Fri Sep 4 19:20:44 CEST 2009

On Fri, Sep 4, 2009 at 10:07 AM, Rudolf Marek<r.marek at assembler.cz> wrote:

> I think the only proper way is to do type1 and maybe some locking is
> necessary.

but our thread subject is "unstable fam10h". Given that fam10h is the
problem, and that it supports MMCONF, why not make new versions of the
functions for processors that have MMCONF and use them on those

We've never seen this kind of problem on K8 AFAIK. We can continue to
use the old functions on those old CPUs.

So, what I'm trying to say:
- we have a problem on fam10h
- it seems to be a non-smp-safe function doing a config cycle
- there are two ways to eliminate the problem
  o write a fam10 version of that function that will use MMCONF (will
work on all later CPUs)
  o modify old function by adding a lock  (i.e. stick with legacy
mechanism for older CPUs)

I just can't see a good reason to stick with the type 1 access when
the fam10h and, presumably all later families, will
support MMCONF. The cf8/cfc is a 15-year-old idea (at least) that
predates smp and multicore. We should be
trying to eliminate that old mechanism whenever we can (at least it
seems that way to me). It is the cf8/cfc mechanism that is the
problem, not the lack of locking.


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