[coreboot] AMD AP core startup problem
scott at notabs.org
Tue Oct 12 22:25:15 CEST 2010
]From: coreboot-bounces at coreboot.org [mailto:coreboot-bounces at coreboot.org] On Behalf Of Arne Georg ]Gleditsch
]"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.
Thanks. Enabling MMIO config space access makes a huge improvement.
I already had everything esle ready. All I had to do was enable
CONFIG_MMCONF_SUPPORT_DEFAULT. Now the problem appears to be solved.
Great work on this feature.
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