diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-pci | 10 | ||||
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 39 |
2 files changed, 29 insertions, 20 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 6615fda0abfb..ee6c04036492 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -65,6 +65,16 @@ Description: force a rescan of all PCI buses in the system, and re-discover previously removed devices. +What: /sys/bus/pci/devices/.../msi_bus +Date: September 2014 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a zero value to this attribute disallows MSI and + MSI-X for any future drivers of the device. If the device + is a bridge, MSI and MSI-X will be disallowed for future + drivers of all child devices under the bridge. Drivers + must be reloaded for the new setting to take effect. + What: /sys/bus/pci/devices/.../msi_irqs/ Date: September, 2011 Contact: Neil Horman <nhorman@tuxdriver.com> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 9ff0a901ecf7..dbf63e23988d 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -250,46 +250,45 @@ static ssize_t msi_bus_show(struct device *dev, struct device_attribute *attr, char *buf) { struct pci_dev *pdev = to_pci_dev(dev); + struct pci_bus *subordinate = pdev->subordinate; - if (!pdev->subordinate) - return 0; - - return sprintf(buf, "%u\n", - !(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI)); + return sprintf(buf, "%u\n", subordinate ? + !(subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI) + : !pdev->no_msi); } static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct pci_dev *pdev = to_pci_dev(dev); + struct pci_bus *subordinate = pdev->subordinate; unsigned long val; if (kstrtoul(buf, 0, &val) < 0) return -EINVAL; - /* - * Bad things may happen if the no_msi flag is changed - * while drivers are loaded. - */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; /* - * Maybe devices without subordinate buses shouldn't have this - * attribute in the first place? + * "no_msi" and "bus_flags" only affect what happens when a driver + * requests MSI or MSI-X. They don't affect any drivers that have + * already requested MSI or MSI-X. */ - if (!pdev->subordinate) + if (!subordinate) { + pdev->no_msi = !val; + dev_info(&pdev->dev, "MSI/MSI-X %s for future drivers\n", + val ? "allowed" : "disallowed"); 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) ^ - !!val) { - pdev->subordinate->bus_flags ^= PCI_BUS_FLAGS_NO_MSI; - - dev_warn(&pdev->dev, "forced subordinate bus to%s support MSI, bad things could happen\n", - val ? "" : " not"); } + if (val) + subordinate->bus_flags &= ~PCI_BUS_FLAGS_NO_MSI; + else + subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI; + + dev_info(&subordinate->dev, "MSI/MSI-X %s for future drivers of devices on this bus\n", + val ? "allowed" : "disallowed"); return count; } static DEVICE_ATTR_RW(msi_bus); |