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    SubjectRe: [tip:x86/pci] x86, pci: Ignore any PCI BARs that match an HPET we already know about
    On 09/22/2010 02:22 PM, tip-bot for Bjorn Helgaas wrote:
    > Commit-ID: e72a6c8f7ac715a9cdb473afbc30743348d0a1e2
    > Gitweb: http://git.kernel.org/tip/e72a6c8f7ac715a9cdb473afbc30743348d0a1e2
    > Author: Bjorn Helgaas <bjorn.helgaas@hp.com>
    > AuthorDate: Wed, 22 Sep 2010 14:15:47 -0600
    > Committer: H. Peter Anvin <hpa@linux.intel.com>
    > CommitDate: Wed, 22 Sep 2010 13:29:39 -0700
    >
    > x86, pci: Ignore any PCI BARs that match an HPET we already know about
    >
    > We often discover the HPET early, via the static ACPI HPET table,
    > before enumerating PCI devices. If the HPET is implemented as a PCI
    > function, we will discover it again during PCI device enumeration. We
    > must ignore the PCI function so we don't inadvertently move it out
    > from under the driver.
    >
    > I think it's better to ignore *any* PCI BAR that matches a previously
    > discovered HPET; that way we don't need platform-specific knowledge,
    > and we won't have to add more quirks for future machines.
    >
    > This is for a regression from 2.6.34, but the reporter has been
    > unable to test it yet.
    >
    > [ hpa: if this fixes the regression, it should be promoted to x86/urgent ]
    >
    > Reference: https://bugzilla.kernel.org/show_bug.cgi?id=18482
    > Reported-by: Simon Arlott <simon@fire.lp0.eu>
    > Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
    > LKML-Reference: <20100922201547.3197.33702.stgit@bob.kio>
    > Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
    > ---
    > arch/x86/kernel/quirks.c | 21 +++++++++++++++++++++
    > arch/x86/pci/fixup.c | 28 ----------------------------
    > 2 files changed, 21 insertions(+), 28 deletions(-)
    >
    > diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
    > index 939b9e9..99a7d4b 100644
    > --- a/arch/x86/kernel/quirks.c
    > +++ b/arch/x86/kernel/quirks.c
    > @@ -507,6 +507,27 @@ static void force_disable_hpet_msi(struct pci_dev *unused)
    > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS,
    > force_disable_hpet_msi);
    >
    > +static void disable_pci_hpet(struct pci_dev *dev)
    > +{
    > + int i;
    > +
    > + if (!hpet_address)
    > + return;
    > +
    > + for (i = 0; i < 6; i++) {
    > + struct resource *res = &dev->resource[i];
    > +
    > + if (resource_type(res) == IORESOURCE_MEM &&
    > + res->start == hpet_address) {
    > + dev_info(&dev->dev, "BAR %d: %pR is an HPET we found earlier; ignoring this BAR\n",
    > + i, res);
    > + res->flags = 0;
    > + res->start = 0;
    > + res->end = 0;
    > + }
    > + }
    > +}

    It seems there is some problem here:

    hpet_res is inserted to resource with late_initcall().
    so if you don't touch that hpet address in bar and not put in the resource.
    kernel could allocate that address to other devices that doesn't get resource from BIOS.

    Yinghai


    > +DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, disable_pci_hpet);
    > #endif
    >
    > #if defined(CONFIG_PCI) && defined(CONFIG_NUMA)
    > diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
    > index 6dd8955..08eba69 100644
    > --- a/arch/x86/pci/fixup.c
    > +++ b/arch/x86/pci/fixup.c
    > @@ -493,31 +493,3 @@ static void __devinit pci_siemens_interrupt_controller(struct pci_dev *dev)
    > }
    > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_SIEMENS, 0x0015,
    > pci_siemens_interrupt_controller);
    > -
    > -/*
    > - * SB600: Disable BAR1 on device 14.0 to avoid HPET resources from
    > - * confusing the PCI engine:
    > - */
    > -static void sb600_disable_hpet_bar(struct pci_dev *dev)
    > -{
    > - u8 val;
    > -
    > - /*
    > - * The SB600 and SB700 both share the same device
    > - * ID, but the PM register 0x55 does something different
    > - * for the SB700, so make sure we are dealing with the
    > - * SB600 before touching the bit:
    > - */
    > -
    > - pci_read_config_byte(dev, 0x08, &val);
    > -
    > - if (val < 0x2F) {
    > - outb(0x55, 0xCD6);
    > - val = inb(0xCD7);
    > -
    > - /* Set bit 7 in PM register 0x55 */
    > - outb(0x55, 0xCD6);
    > - outb(val | 0x80, 0xCD7);
    > - }
    > -}
    > -DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_ATI, 0x4385, sb600_disable_hpet_bar);
    > --
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