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SubjectRe: [PATCH] x86/PCI: never allocate PCI space from the last 1M below 4G
On Mon, Nov 29, 2010 at 2:04 PM, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
>
> I think we're talking about whether to reserve the top 1MB or top 2MB.
> I freely admit I don't know the right answer.  My point is merely that
> since we're using a heuristic anyway, copying Windows is a pretty good
> starting point.  In my mind, doing something different requires a
> stronger argument than "it might fix some machines where Windows is
> broken."

What's the status of this? The original patch is pretty nasty, and I
think that hack to put things in the bios_align_resource() function is
just disgusting.

And why is the fix not the really _trivial_ one, which does just this:

diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
index ca0437c..aef9f77 100644
--- a/arch/x86/include/asm/pci.h
+++ b/arch/x86/include/asm/pci.h
@@ -141,7 +141,7 @@ void dma32_reserve_bootmem(void);

/* generic pci stuff */
#include <asm-generic/pci.h>
-#define PCIBIOS_MAX_MEM_32 0xffffffff
+#define PCIBIOS_MAX_MEM_32 0xfff00000

#ifdef CONFIG_NUMA
/* Returns the node based on pci bus */

Hmm?

(Ok, so that doesn't protect a 64-bit resource that just happens to be
inside a window that ends at 0xffffffff, but if you have those kinds
of bus windows, that means that there's nothing there at the 4GB mark
anyway, no?)

Linus

Linus
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