Re: [Qemu-devel] [PATCH] pci: fix bridge IO/BASE

[Mark Cave-Ayland]

On 04/03/12 19:51, Blue Swirl wrote:

> I now know the root cause of the problem. OpenBIOS programs the BARs
> somewhat correctly just by accident. The initial io_base and mem_base
> for BARs are not correct, but because the host bridge BARs (and also 6
> of which 4 are not even BARs!) are programmed first, the bases
> happened to settle to values that happen to work. The commit revealed
> the problem since the settling didn't happen. The mask changes just
> let the host bridge setup continue to do the magic.
>
> By just changing OpenBIOS (see attached patch), I can get the devices
> to work (assuming that VGA is a separate problem). There's no need to
> change QEMU.

Hi Blue/Michael,

Thanks for debugging this. I can confirm that building OpenBIOS SVN 
trunk with Blue's patch and testing against QEMU git master with the 
attached patch (to temporarily back out 
2b50aa1f14d8e0a40f905ad0c022443c15646914 and 
de58ac72b6a062d1a61478284c0c0f8a0428613e which breaks VGA on 
PPC/SPARC64) appears to fix the problem for me.

Thanks a lot to both of you for taking the time to track this down :)


ATB,

Mark.

qemu-mem-revert.patch
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