[PATCH] PCI: make MSI quirk inheritable from the pci bus

It turns out AMD 8131 quirk only affects MSI for devices behind the 8131 bridge.
Handle this by adding a flags field in pci_bus, inherited from parent to child.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 15 insertions, 3 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index d5a67c1bcb98..4de1c17ee573 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -703,6 +703,9 @@ int pci_enable_msi(struct pci_dev* dev)
         if (dev->no_msi)
                 return status;
 
+        if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
+                return -EINVAL;
+
         temp = dev->irq;
 
         status = msi_init();
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 3bc0fcd71d03..542e7dfb371b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -347,6 +347,7 @@ pci_alloc_child_bus(struct pci_bus *parent, struct pci_dev *bridge, int busnr)
         child->parent = parent;
         child->ops = parent->ops;
         child->sysdata = parent->sysdata;
+        child->bus_flags = parent->bus_flags;
         child->bridge = get_device(&bridge->dev);
 
         child->class_dev.class = &pcibus_class;
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index d71c31df7fdf..4970f47be72c 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -575,8 +575,11 @@ static void __init quirk_amd_8131_ioapic(struct pci_dev *dev)
 { 
         unsigned char revid, tmp;
         
-        pci_msi_quirk = 1;
-        printk(KERN_WARNING "PCI: MSI quirk detected. pci_msi_quirk set.\n");
+        if (dev->subordinate) {
+                printk(KERN_WARNING "PCI: MSI quirk detected. "
+                       "PCI_BUS_FLAGS_NO_MSI set for subordinate bus.\n");
+                dev->subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
+        }
 
         if (nr_ioapics == 0) 
                 return;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2039da1f3672..d4d533fa5d30 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -95,6 +95,11 @@ enum pci_channel_state {
         pci_channel_io_perm_failure = (__force pci_channel_state_t) 3,
 };
 
+typedef unsigned short __bitwise pci_bus_flags_t;
+enum pci_bus_flags {
+        PCI_BUS_FLAGS_NO_MSI = (pci_bus_flags_t) 1,
+};
+
 /*
  * The pci_dev structure is used to describe PCI devices.
  */
@@ -203,7 +208,7 @@ struct pci_bus {
         char            name[48];
 
         unsigned short  bridge_ctl;     /* manage NO_ISA/FBB/et al behaviors */
-        unsigned short  pad2;
+        pci_bus_flags_t bus_flags;      /* Inherited by child busses */
         struct device           *bridge;
         struct class_device     class_dev;
         struct bin_attribute    *legacy_io; /* legacy I/O for this bus */