Re: [Bug] pci allocation resources problems on x86_64

From: mathieu . taillefumier
Date: Fri Oct 24 2008 - 16:18:01 EST


Hi,

> Ultimately we need to do better at grabbing space for PCI allocations on x86.
> I was hoping we'd have some patches in 2.6.28 that would help here, but they
> weren't ready in time. Can you file a kernel.org bug for this problem with
> the files attached? I'll try to find time to put together some
> improvements...

yes sure. I will do that this weekend. I already grab some more information
about this problem by reading docs. The problem seems related to iommu setup
since it is not activated when the mem < 3G but activated when the mem>3G. I do
not understand however how the kernel can report more that 4g of memory when
there are only 4g installed (So I think that the bios is buggy too). I also
remarked that the size of the /proc/mem file is not what it is intended to be.
Another supprizing thing is these lines of the dmesg-not-working file

pci 0000:0a:00.0: BAR 0: got res [0x140000000-0x1400007ff] bus [0x140000000-0x14
00007ff] flags 0x20200
pci 0000:0a:00.0: BAR 0: moved to bus [0x140000000-0x1400007ff] flags 0x20200

it seems that the drivers setup some resources that way behind the available
memory.

Regards

MAthieu
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