4 files changed, 22 insertions, 2 deletions
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index d3dcce8..4d762fc 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -11,6 +11,10 @@ config PCI_MSI
 	   generate an interrupt using an inbound Memory Write on its
 	   PCI bus instead of asserting a device IRQ pin.
 
+	   Use of PCI MSI interrupts can be disabled at kernel boot time
+	   by using the 'pci=nomsi' option.  This disables MSI for the
+	   entire system.
+
 	   If you don't know what to do here, say N.
 
 config PCI_DEBUG
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index aea8b25..a77e79c 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -765,8 +765,11 @@ void pci_disable_msi(struct pci_dev* dev)
 	u16 control;
 	unsigned long flags;
 
+	if (!pci_msi_enable)
+		return;
 	if (!dev)
 		return;
+
 	pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 	if (!pos)
 		return;
@@ -1026,6 +1029,8 @@ void pci_disable_msix(struct pci_dev* dev)
 	int pos, temp;
 	u16 control;
 
+	if (!pci_msi_enable)
+		return;
 	if (!dev)
 		return;
 
@@ -1152,6 +1157,11 @@ void msi_remove_pci_irq_vectors(struct pci_dev* dev)
 	}
 }
 
+void pci_no_msi(void)
+{
+	pci_msi_enable = 0;
+}
+
 EXPORT_SYMBOL(pci_enable_msi);
 EXPORT_SYMBOL(pci_disable_msi);
 EXPORT_SYMBOL(pci_enable_msix);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0bf6d25..03af232 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -900,8 +900,12 @@ static int __devinit pci_setup(char *str)
 		if (k)
 			*k++ = 0;
 		if (*str && (str = pcibios_setup(str)) && *str) {
-			/* PCI layer options should be handled here */
-			printk(KERN_ERR "PCI: Unknown option `%s'\n", str);
+			if (!strcmp(str, "nomsi")) {
+				pci_no_msi();
+			} else {
+				printk(KERN_ERR "PCI: Unknown option `%s'\n",
+						str);
+			}
 		}
 		str = k;
 	}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a6dfee2..8f3fb47 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -50,8 +50,10 @@ extern int pci_msi_quirk;
 
 #ifdef CONFIG_PCI_MSI
 void disable_msi_mode(struct pci_dev *dev, int pos, int type);
+void pci_no_msi(void);
 #else
 static inline void disable_msi_mode(struct pci_dev *dev, int pos, int type) { }
+static inline void pci_no_msi(void) { }
 #endif
 
 extern int pcie_mch_quirk;