From: Ben Hutchings commit fcd097f31a6ee207cc0c3da9cccd2a86d4334785 upstream. During suspend on an SMP system, {read,write}_msi_msg_desc() may be called to mask and unmask interrupts on a device that is already in a reduced power state. At this point memory-mapped registers including MSI-X tables are not accessible, and config space may not be fully functional either. While a device is in a reduced power state its interrupts are effectively masked and its MSI(-X) state will be restored when it is brought back to D0. Therefore these functions can simply read and write msi_desc::msg for devices not in D0. Further, read_msi_msg_desc() should only ever be used to update a previously written message, so it can always read msi_desc::msg and never needs to touch the hardware. Tested-by: "Michael Chan" Signed-off-by: Ben Hutchings Signed-off-by: Jesse Barnes Signed-off-by: Greg Kroah-Hartman --- drivers/pci/msi.c | 36 ++++++++++++------------------------ 1 file changed, 12 insertions(+), 24 deletions(-) --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -195,30 +195,15 @@ void unmask_msi_irq(unsigned int irq) void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) { struct msi_desc *entry = get_irq_desc_msi(desc); - if (entry->msi_attrib.is_msix) { - void __iomem *base = entry->mask_base + - entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE; - msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR); - msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR); - msg->data = readl(base + PCI_MSIX_ENTRY_DATA); - } else { - struct pci_dev *dev = entry->dev; - int pos = entry->msi_attrib.pos; - u16 data; - - pci_read_config_dword(dev, msi_lower_address_reg(pos), - &msg->address_lo); - if (entry->msi_attrib.is_64) { - pci_read_config_dword(dev, msi_upper_address_reg(pos), - &msg->address_hi); - pci_read_config_word(dev, msi_data_reg(pos, 1), &data); - } else { - msg->address_hi = 0; - pci_read_config_word(dev, msi_data_reg(pos, 0), &data); - } - msg->data = data; - } + /* We do not touch the hardware (which may not even be + * accessible at the moment) but return the last message + * written. Assert that this is valid, assuming that + * valid messages are not all-zeroes. */ + BUG_ON(!(entry->msg.address_hi | entry->msg.address_lo | + entry->msg.data)); + + *msg = entry->msg; } void read_msi_msg(unsigned int irq, struct msi_msg *msg) @@ -231,7 +216,10 @@ void read_msi_msg(unsigned int irq, stru void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) { struct msi_desc *entry = get_irq_desc_msi(desc); - if (entry->msi_attrib.is_msix) { + + if (entry->dev->current_state != PCI_D0) { + /* Don't touch the hardware now */ + } else if (entry->msi_attrib.is_msix) { void __iomem *base; base = entry->mask_base + entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/