Re: [PATCH] PCI MSI: Yet another fix for MSI-X with NIU cards, v2

From: Michael Ellerman
Date: Wed May 13 2009 - 02:31:42 EST


On Wed, 2009-05-13 at 14:06 +0900, Hidetoshi Seto wrote:
> The NIU device refuses to allow accesses to MSI-X registers before MSI-X
> is enabled. This patch fixes the problem by moving the read & write the
> mask register (for preserved bits) to after MSI-X is enabled.
>
> Reported-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
> ---
> drivers/pci/msi.c | 21 ++++++++++++++++++---
> 1 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 6f2e629..44085e0 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -455,9 +455,7 @@ static int msix_capability_init(struct pci_dev *dev,
> entry->msi_attrib.default_irq = dev->irq;
> entry->msi_attrib.pos = pos;
> entry->mask_base = base;
> - entry->masked = readl(base + j * PCI_MSIX_ENTRY_SIZE +
> - PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
> - msix_mask_irq(entry, 1);
> + entry->masked = 1;
>
> list_add_tail(&entry->list, &dev->msi_list);
> }
> @@ -493,6 +491,23 @@ static int msix_capability_init(struct pci_dev *dev,
> msix_set_enable(dev, 1);
> dev->msix_enabled = 1;
>
> + /*
> + * The states of Reserved bits[31:01] of Vector Control for MSI-X
> + * Table Entries must be 0. However, for potential future use,
> + * software must preserve the value of these reserved bits.
> + * Refer PCI spec 3.0, 6.8.2.9.
> + *
> + * Note that there are some device that refuses access to MSI-X
> + * Table Entries before MSI-X is enabled. Therefore we do it here.
> + */
> + list_for_each_entry(entry, &dev->msi_list, list) {
> + int vector = entry->msi_attrib.entry_nr;
> + entry->masked = readl(base + vector * PCI_MSIX_ENTRY_SIZE +
> + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
> + /* Make sure it is masked */
> + msix_mask_irq(entry, 1);
> + }
> +
> return 0;
> }

That looks better to me, hopefully it fixes DaveM's device too :)

Acked-by: Michael Ellerman <michael@xxxxxxxxxxxxxx>

cheers


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