[coreboot] [PATCH] Add support for Asus M4A785-M, with build instructions

Juhana Helovuo juhe at iki.fi
Mon Sep 13 18:08:35 CEST 2010

On Mon, 2010-09-13 at 09:08 -0600, Myles Watson wrote:

> Thanks for tracking it down.  I committed the patches as
> Rev 5805 (PCI & SB700)
> Rev 5806 (Multiboot tables)
> Rev 5807 (fam10 UMA)
> Rev 5808 (fam10 reserved regions)
> Rev 5809 (Asus M4A785-M)

Thanks a lot for all your troubles and advice!

> > * 5796 + your simplified patches --> SATA failure
> >
> > It seems to me that the patches are ok, but some trunk change from 5795
> > to 5796 is causing the problems.
> There seems to be a problem with CONFIG_MMCONF_SUPPORT vs.
> This should work for you until it's fixed.  If it doesn't, I need to
> dig a little deeper.

Hmm. I just checked out 5810 and tested. Configuration and building go
smoothly  (although menuconfig gives wrong ROM size by default, should
be 1 MByte), but Linux still fails on SATA and USB.

I edited away MMCONF_SUPPORT before configuring like you wrote, but it
does not help.

Also, I ran into another problem:

When I upgrade RAM from 2 GB to 4 GB (or 6 GB), executing the VGA BIOS
gets stuck. Coreboot jumps into the BIOS code, but it never returns.

With more RAM, the UMA gets mapped to 0xd0000000 and PCI iomem areas get
mapped over real RAM, starting at 0xe0000000. In the boot log I found
the following line:

Warning: Can't set up MTRR hole for UMA due to pre-existing MTRR hole.

This message does not appear with 2 GB RAM.

More test results with 6 GB RAM:

* If I disable the GFXUMA option, do not include VGA BIOS on CBFS, and
install another VGA card in a PCI slot, I get the same results. Coreboot
locates the BIOS on the external card, copies to low RAM, jumps into it,
and gets stuck.

* If I hardwire UMA start address to be 0x70000000 and UMA size 64M in
mainboard.c, the BIOS does not get stuck and Coreboot launches Grub2.
However, Grub2 is very unstable and crashes randomly. I also sometimes
get random garbage on VGA. Loading Linux does not work, causes machine
to get stuck or reboot.

Apparently there is some address conflict, but where should I start

Best Regards,
Juhana Helovuo

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