[coreboot] PCI MMCONF on amdfam10

Kyösti Mälkki kyosti.malkki at gmail.com
Fri Dec 13 11:29:00 CET 2013

On 12/13/2013 01:34 AM, Stefan Reinauer wrote:
> * Kyösti Mälkki <kyosti.malkki at gmail.com> [131212 16:02]:
>> Hi
>> After commit 872c922 there is some trouble on PCI configuration
>> access with Asus M4A785-M. This could apply to other amdfam10 too,
>> although I have not yet received such reports.
>> As the commit message stated, I had discovered that in the beginning
>> of ramstage all PCI configuration access used the IO (0xcf8) method
>> even though Kconfig specified MMCONF_SUPPORT_DEFAULT which should
>> imply all PCI config access is done with MMCONF unless IO is
>> explicitly requested.
> Not sure if this is relevant, but on i945 not all PCI devices are
> visible in MMCONF space. So enabling MMCONF_SUPPORT_DEFAULT there will
> break the system.
> Stefan

Yet we have had commit 032c23db for 5 months:


   Change all PCI configuration accesses to MMIO on all boards
   with i945 chipset. To enable MMIO style access, add explicit
   PCI IO config write in the bootblock.

I remember a week or so after this was merged you made that comment 
about i945 on a related change. I requested literature reference or a 
test case to see if I should revert. I got neither and the revert never 
took place.

Until you are  more specific on your statement, I am reading it as follows:

   Stefan added 'select MMCONF_SUPPORT_DEFAULT' on a mainboard with i945
   and the board did not boot.

I am not saying yout statement is incorrect, but how about some 


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