On Fri, Aug 22, 2014 at 04:07:58PM +0800, Yijing Wang wrote:
> Msi_bus attribute is only valid for bridge device.
> We can enable or disable MSI capability for a bus,
> if we echo 1/0 > /sys/bus/pci/devices/$EP/msi_bus,
> the action will be ignored. Sometime we need to
> only enable/disable a EP device MSI capability,
> not all devices share the same bus.
>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
What's the purpose of this? Is this just for debugging? I assume that if
you have an endpoint that requires MSI to be disabled, you'd have a quirk
to do that, not a sysfs interface.
This should probably be mentioned in
Documentation/ABI/testing/sysfs-bus-pci while you're at it. I know it's
not there yet, but this seems like a good time to rectify that omission.
> ---
> drivers/pci/pci-sysfs.c | 12 ++++++------
> 1 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 9ff0a90..b199ad9 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -251,11 +251,9 @@ static ssize_t msi_bus_show(struct device *dev, struct device_attribute *attr,
> {
> struct pci_dev *pdev = to_pci_dev(dev);
>
> - if (!pdev->subordinate)
> - return 0;
> -
> - return sprintf(buf, "%u\n",
> - !(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI));
> + return sprintf(buf, "%u\n", pdev->subordinate ?
> + !(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI)
> + : !pdev->no_msi);
> }
>
> static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr,
> @@ -278,8 +276,10 @@ static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr,
> * Maybe devices without subordinate buses shouldn't have this
> * attribute in the first place?
> */
> - if (!pdev->subordinate)
> + if (!pdev->subordinate) {
> + pdev->no_msi = !val;
> return count;
> + }
>
> /* Is the flag going to change, or keep the value it already had? */
> if (!(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI) ^
> --
> 1.7.1
>
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