Re: [2.6.34-rc1 REGRESSION] ahci 0000:00:1f.2: controller reset failed (0xffffffff)

["H. Peter Anvin" <hpa@zytor.com>]

On 04/12/2010 10:56 AM, Bjorn Helgaas wrote:
> 
> Linux thinks the windows are:
>   pci_root PNP0A03:00: host bridge window [mem 0x000a0000-0x000bffff]
>   pci_root PNP0A03:00: host bridge window [mem 0x000c0000-0x000effff]
>   pci_root PNP0A03:00: host bridge window [mem 0x000f0000-0x000fffff]
> 
> The 0xa0000-0xbffff one makes good sense.  That's normally MMIO that's
> routed via PCI to the VGA device frame buffer, and we should be able
> to figure out how to avoid that area, e.g., by using BIOS info, PCI
> class codes, etc.
> 
> Now we need to figure how to avoid the 0xc0000-0xeffff and 0xf0000-0xfffff
> windows.  Maybe there's something special about how ACPI describes them.
> 
> Or maybe we're just unlucky because these are the first windows in the
> _CRS list, and Linux tries them in order, while Windows uses a different
> strategy.
> 

I strongly suspects that Windows knows that < 1 MB is special, and only
ever assigns it upon explicit allocation.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.