diff options
Diffstat (limited to 'drivers/pci/pci-sysfs.c')
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 39 |
1 files changed, 19 insertions, 20 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 76ef7914c9aa..92b6d9ab00e4 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); |