MSI: Cleanup existing MSI quirks

Move MSI quirks in CONFIG_PCI_MSI, document why the serverworks quirk
does not simply set PCI_BUS_FLAGS_NO_MSI, and create a generic quirk
for other chipsets where setting PCI_BUS_FLAGS_NO_MSI is fine.
Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/pci.h

@@ -42,7 +42,7 @@ extern void pci_remove_legacy_files(struct pci_bus *bus);
 /* Lock for read/write access to pci device and bus lists */
 extern struct rw_semaphore pci_bus_sem;
 
-#ifdef CONFIG_X86_IO_APIC
+#ifdef CONFIG_PCI_MSI
 extern int pci_msi_quirk;
 #else
 #define pci_msi_quirk 0

drivers/pci/quirks.c

@@ -577,8 +577,6 @@ static void __init quirk_ioapic_rmw(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SI,	PCI_ANY_ID,			quirk_ioapic_rmw );
 
-int pci_msi_quirk;
-
 #define AMD8131_revA0        0x01
 #define AMD8131_revB0        0x11
 #define AMD8131_MISC         0x40
@@ -587,12 +585,6 @@ static void __init quirk_amd_8131_ioapic(struct pci_dev *dev)
 { 
         unsigned char revid, tmp;
         
-	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;
 
@@ -605,13 +597,6 @@ static void __init quirk_amd_8131_ioapic(struct pci_dev *dev)
         }
 } 
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8131_BRIDGE, quirk_amd_8131_ioapic);
-
-static void __init quirk_svw_msi(struct pci_dev *dev)
-{
-	pci_msi_quirk = 1;
-	printk(KERN_WARNING "PCI: MSI quirk detected. pci_msi_quirk set.\n");
-}
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_GCNB_LE, quirk_svw_msi );
 #endif /* CONFIG_X86_IO_APIC */
 
 
@@ -1690,6 +1675,36 @@ static void __devinit quirk_nvidia_ck804_pcie_aer_ext_cap(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA,  PCI_DEVICE_ID_NVIDIA_CK804_PCIE,
 			quirk_nvidia_ck804_pcie_aer_ext_cap);
 
+#ifdef CONFIG_PCI_MSI
+/* To disable MSI globally */
+int pci_msi_quirk;
+
+/* The Serverworks PCI-X chipset does not support MSI. We cannot easily rely
+ * on setting PCI_BUS_FLAGS_NO_MSI in its bus flags because there are actually
+ * some other busses controlled by the chipset even if Linux is not aware of it.
+ * Instead of setting the flag on all busses in the machine, simply disable MSI
+ * globally.
+ */
+static void __init quirk_svw_msi(struct pci_dev *dev)
+{
+	pci_msi_quirk = 1;
+	printk(KERN_WARNING "PCI: MSI quirk detected. pci_msi_quirk set.\n");
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_GCNB_LE, quirk_svw_msi);
+
+/* Disable MSI on chipsets that are known to not support it */
+static void __devinit quirk_disable_msi(struct pci_dev *dev)
+{
+	if (dev->subordinate) {
+		printk(KERN_WARNING "PCI: MSI quirk detected. "
+		       "PCI_BUS_FLAGS_NO_MSI set for %s subordinate bus.\n",
+		       pci_name(dev));
+		dev->subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
+	}
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8131_BRIDGE, quirk_disable_msi);
+#endif /* CONFIG_PCI_MSI */
+
 EXPORT_SYMBOL(pcie_mch_quirk);
 #ifdef CONFIG_HOTPLUG
 EXPORT_SYMBOL(pci_fixup_device);