Messages in this thread | | | Date | Tue, 09 Jul 2013 13:43:46 +0800 | From | ZhenHua <> | Subject | Re: [PATCH 1/1] ia64/pci: set mmio decoding on for some host bridge |
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Hi Bjorn, Thank you for reviewing this patch. I have created a new one and sent it out. And your questions are answered in that new wmail.
Regards ZhenHua
On 07/09/2013 04:35 AM, Bjorn Helgaas wrote: > On Sun, Jul 7, 2013 at 6:16 PM, Li, Zhen-Hua <zhen-hual@hp.com> wrote: >> On some IA64 platforms with intel PCI bridge, for example, HP BL890c i2 >> with Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port, >> when kernel tries to disable the mmio decoding on the PCI bridge devices, >> kernel may crash. >> >> And in the comment of function quirk_mmio_always_on, it also says: >> "But doing so (disable the mmio decoding) may cause problems on host bridge >> and perhaps other key system devices" >> >> So, for these PCI bridges, dev->mmio_always_on bit should be set to 1. >> >> >> Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com> >> --- >> drivers/pci/quirks.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c >> index e85d230..24b8024 100644 >> --- a/drivers/pci/quirks.c >> +++ b/drivers/pci/quirks.c >> @@ -44,6 +44,21 @@ static void quirk_mmio_always_on(struct pci_dev *dev) >> DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID, >> PCI_CLASS_BRIDGE_HOST, 8, quirk_mmio_always_on); >> >> +#ifdef CONFIG_IA64 >> +/* >> + * On some IA64 platforms, for some intel PCI bridge devices, for example, >> + * the Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port, >> + * disable the mmio decoding on these devices may cause system crash. >> + * So dev->mmio_always_on bit should be set to 1. >> + */ >> +static void quirk_mmio_on_intel_pcibridge(struct pci_dev *dev) >> +{ >> + dev->mmio_always_on = 1; >> +} >> +DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID, >> + PCI_CLASS_BRIDGE_PCI, 8, quirk_mmio_on_intel_pcibridge); >> +#endif > The changelog and comment suggest an issue specific to Intel > 5520/5500/X58, but the patch sets mmio_always_on for *all* PCI > bridges. > > It claims to be specific to ia64 (and is only compiled there), but the > chipset is also used for x86. You need to explain why the problem > only affects ia64. > > Bjorn
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