[coreboot] pci_read_config8 crash in mainboard.c

Marc Jones marcj303 at gmail.com
Tue Mar 3 19:22:15 CET 2009

I think I see the problem. The mainboard.c code is called during the
chip_operations enable_dev stage very early before the static tree is
setup with the device function pointers. The reason for this is to do
chip device setup before the devices are scanned. For example the
device may need to be enabled in the southbridge before it will be
found in the normal scan or it may need to be hidden etc.

If you look at static.c you will see that the .ops = 0 for all the
devices. That field gets updated in set_pci_ops() (or other device ops
setup functions) which happens later in the device scan, after the
chip enable_dev.

That is why we need to use the direct access pci functions and not the
static tree pointer functions. I think that the fix is to add a
comment explaining why you need to use the direct access functions at
in the enable_dev function.

I hope that was clear. It is a bit easier to understand in V3 where
the stages/phases are numbered.


More information about the coreboot mailing list