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Date: Mon, 29 Nov 2010 18:36:20 +0000
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jesse Barnes <jbarnes@virtuousgeek.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] x86/PCI: never allocate PCI space from the last 1M
	below 4G
Message-ID: <20101129183620.GA14591@srcf.ucam.org>
References: <20101129183009.11256.33739.stgit@bob.kio>
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On Mon, Nov 29, 2010 at 11:30:09AM -0700, Bjorn Helgaas wrote:
> 
> The last 1M before 4G contains the processor restart vector and usually
> the system ROM.  We don't know the actual ROM size; I chose 1M because
> that's how much Windows 7 appears to avoid.
> 
> Without this check, we can allocate PCI space that will never work.  On
> Matthew's HP 2530p, we put the Intel GTT "Flush Page" at the very last
> page, which causes a spontaneous power-off:
> 
>   pci_root PNP0A08:00: host bridge window [mem 0xfee01000-0xffffffff]
>   fffff000-ffffffff : Intel Flush Page (assigned by intel-gtt)
> 
> Reference: https://bugzilla.kernel.org/show_bug.cgi?id=23542
> Reported-by: Matthew Garrett <mjg@redhat.com>
> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>

Tested-by: Matthew Garrett <mjg@redhat.com>

-- 
Matthew Garrett | mjg59@srcf.ucam.org
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