Re: [PATCH] PCI/MSI: Don't set up INTx if MSI or MSI-X is enabled

From: Andy Shevchenko
Date: Wed Mar 14 2018 - 12:31:46 EST


On Tue, Mar 13, 2018 at 11:45 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>

Agree with Christoph's comment.

> If a device already has MSI or MSI-X enabled, there's no need to set up its
> legacy INTx interrupt.

Just point to the actual behaviour of this. In some cases code in
question has to distinguish between MSI and MSI-x.
So, this or similar changes has to be done with keeping above in mind.

(Existing example is Thunderbolt driver)

>
> bba6f6fc68e7 ("[PATCH] MSI-X: fix resume crash") changed the cris, frv,
> x86, and ia64 arches to skip INTx setup when MSI is enabled.
>
> 16cf0ebc35dd ("x86/PCI: Do not use interrupt links for devices using
> MSI-X") extended that by changing x86 to also skip INTx setup when MSI-X is
> enabled.
>
> Change the remaining arches (cris, frv, and ia64) to skip INTx setup when
> either MSI or MSI-X is enabled.
>
> Also update mn10300 (which didn't exist at the time of bba6f6fc68e7) to
> follow the same pattern.

Perhaps no need to change the architectures that are about to be
removed completely from the kernel.

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> arch/cris/arch-v32/drivers/pci/bios.c | 2 +-
> arch/frv/mb93090-mb00/pci-vdk.c | 2 +-
> arch/ia64/pci/pci.c | 4 ++--
> arch/mn10300/unit-asb2305/pci.c | 8 +++++---
> 4 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/arch/cris/arch-v32/drivers/pci/bios.c b/arch/cris/arch-v32/drivers/pci/bios.c
> index 6b9e6cfaa29e..c2bed0cc060b 100644
> --- a/arch/cris/arch-v32/drivers/pci/bios.c
> +++ b/arch/cris/arch-v32/drivers/pci/bios.c
> @@ -68,7 +68,7 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
> if ((err = pcibios_enable_resources(dev, mask)) < 0)
> return err;
>
> - if (!dev->msi_enabled)
> + if (!pci_dev_msi_enabled(dev))
> pcibios_enable_irq(dev);
> return 0;
> }
> diff --git a/arch/frv/mb93090-mb00/pci-vdk.c b/arch/frv/mb93090-mb00/pci-vdk.c
> index f211839e2cae..4a55d1b82d21 100644
> --- a/arch/frv/mb93090-mb00/pci-vdk.c
> +++ b/arch/frv/mb93090-mb00/pci-vdk.c
> @@ -413,7 +413,7 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>
> if ((err = pci_enable_resources(dev, mask)) < 0)
> return err;
> - if (!dev->msi_enabled)
> + if (!pci_dev_msi_enabled(dev))
> pcibios_enable_irq(dev);
> return 0;
> }
> diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
> index f5ec736100ee..7ccc64d5fe3e 100644
> --- a/arch/ia64/pci/pci.c
> +++ b/arch/ia64/pci/pci.c
> @@ -398,7 +398,7 @@ pcibios_enable_device (struct pci_dev *dev, int mask)
> if (ret < 0)
> return ret;
>
> - if (!dev->msi_enabled)
> + if (!pci_dev_msi_enabled(dev))
> return acpi_pci_irq_enable(dev);
> return 0;
> }
> @@ -407,7 +407,7 @@ void
> pcibios_disable_device (struct pci_dev *dev)
> {
> BUG_ON(atomic_read(&dev->enable_cnt));
> - if (!dev->msi_enabled)
> + if (!pci_dev_msi_enabled(dev))
> acpi_pci_irq_disable(dev);
> }
>
> diff --git a/arch/mn10300/unit-asb2305/pci.c b/arch/mn10300/unit-asb2305/pci.c
> index 3dfe2d31c67b..4d36ea517679 100644
> --- a/arch/mn10300/unit-asb2305/pci.c
> +++ b/arch/mn10300/unit-asb2305/pci.c
> @@ -399,10 +399,12 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
> {
> int err;
>
> - err = pci_enable_resources(dev, mask);
> - if (err == 0)
> + if ((err = pci_enable_resources(dev, mask)) < 0)
> + return err;
> +
> + if (!pci_dev_msi_enabled(dev))
> pcibios_enable_irq(dev);
> - return err;
> + return 0;
> }
>
> /*
>



--
With Best Regards,
Andy Shevchenko