Re: [PATCH] x86/PCI: never allocate PCI MMIO resources below BIOS_END

From: Jesse Barnes
Date: Mon Apr 26 2010 - 21:40:57 EST


On Mon, 26 Apr 2010 18:27:27 -0700 (PDT)
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

>
>
> On Mon, 26 Apr 2010, Jesse Barnes wrote:
> >
> > Glad we agree. As I said (and echoing Bjorn), I think it would be best
> > to reserve this space in a way that doesn't just use IORESOURCE_BUSY.
> > We want and need to do allocations from the special region, so we
> > should mark it as such.
>
> I think Bjorn's patch to pcibios_align_resource() is really good and
> clever, and I think it should take care of the need for IORESOURCE_BUSY,
> no? We do want to let devices that are _already_ allocated there insert
> their resources, it's just that we never want to allocate new ones in the
> low 1M region.
>
> Do we actually have a regression left with Bjorn's patch?

No, I think we're covered. But it sounded like Peter was also
concerned about making new allocations from the 1M space, which would
mean we'd need something other than the IORESOURCE_BUSY bit. But maybe
Bjorn's patch plus simply removing the IORESOURCE_BUSY line is
sufficient for that. The downside there is that it doesn't clearly
communicate the special nature of the 1M region.

--
Jesse Barnes, Intel Open Source Technology Center
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