[coreboot] AMD AP core startup problem

Arne Georg Gleditsch arne.gleditsch at numascale.com
Tue Oct 12 09:54:07 CEST 2010

"Scott Duplichan" <scott at notabs.org> writes:
> I find with my RS780/SB700 board (ECS A780GM-M3), the initial
> family 10h AP launch is not reliable. I often see a hang when
> when all the cores are running in parallel. The parallel execution
> is apparent if serial logging is enabled, because the characters
> logged by each core are interleaved. I noticed the AP cores do a
> few cf8/cfc pci config writes. Could simultaneous access to this
> shared index/data pair be responsible for the hang? Concerns about
> such conflicts is why the AMD agesa code does not run cores on the
> same die in parallel.

This is actually the main reason I fixed MMCONFIG for AMD boards, since
that avoids the cf8/cfc race.  I would suggest enabling that, but you
might have to change the default address range.  I believe there's a BAR
that's assigned a temporary address by the RS780 code that would clash.


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