[coreboot] AMD Tilapia / simnow: endless looping in functionpci_scan_bus

Juhana Helovuo juhe at iki.fi
Thu Sep 2 09:18:15 CEST 2010

1.9.2010 23:00, Scott kirjoitti:

> Thanks Myles. That problem description and work-around matches my
> situation exactly. Even if the bad value passed to pci_scan_bus is
> only a side-effect of another problem, special handling for it should
> be considered in order to simplify debugging.
> The same thead covers another problem I encounter with Tilapia. When
> I enable ACPI table generation, an overlap causes the seabios payload
> to overwrite the ACPI tables. I temporarily worked around this problem
> by deselecting GFXUMA. I am using PCI video so I can boot with no uma.


I had similar problems recently. I did a patch for Asus M4A785-M, which 
is derived from the AMD Tilapia port.

The patch can be found at

There is another patch that sets up UMA and coreboot/ACPI/etc. tables 
as reserved areas in the multiboot tables. Without this patch booting 
with Grub to Linux suffers from the same problem of overwriting tables.


I do not know if these are going to be integrated to the Coreboot trunk, 
but currently they are available as patch files.

How does SeaBIOS detect which RAM is usable and which is not? Maybe the 
memory conflict with UMA and ACPI tables could be avoided in a similar 

Best regards,
Juhana Helovuo

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