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

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Mon, 26 Apr 2010 18:27:27 -0700 (PDT)
Linus Torvalds <torvalds@linux-foundation.org> 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