diff options
Diffstat (limited to 'drivers/pci/probe.c')
| -rw-r--r-- | drivers/pci/probe.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 19c8950c6c38..8b8826b9a398 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1330,6 +1330,34 @@ static void pci_msi_setup_pci_dev(struct pci_dev *dev) } /** + * pci_intx_mask_broken - test PCI_COMMAND_INTX_DISABLE writability + * @dev: PCI device + * + * Test whether PCI_COMMAND_INTX_DISABLE is writable for @dev. Check this + * at enumeration-time to avoid modifying PCI_COMMAND at run-time. + */ +static int pci_intx_mask_broken(struct pci_dev *dev) +{ + u16 orig, toggle, new; + + pci_read_config_word(dev, PCI_COMMAND, &orig); + toggle = orig ^ PCI_COMMAND_INTX_DISABLE; + pci_write_config_word(dev, PCI_COMMAND, toggle); + pci_read_config_word(dev, PCI_COMMAND, &new); + + pci_write_config_word(dev, PCI_COMMAND, orig); + + /* + * PCI_COMMAND_INTX_DISABLE was reserved and read-only prior to PCI + * r2.3, so strictly speaking, a device is not *broken* if it's not + * writable. But we'll live with the misnomer for now. + */ + if (new != toggle) + return 1; + return 0; +} + +/** * pci_setup_device - fill in class and map information of a device * @dev: the device structure to fill * @@ -1399,6 +1427,8 @@ int pci_setup_device(struct pci_dev *dev) } } + dev->broken_intx_masking = pci_intx_mask_broken(dev); + switch (dev->hdr_type) { /* header type */ case PCI_HEADER_TYPE_NORMAL: /* standard header */ if (class == PCI_CLASS_BRIDGE_PCI) |