--- linux-2.6.30.noarch/Documentation/kernel-parameters.txt~	2009-06-24 14:25:04.000000000 -0400

+++ linux-2.6.30.noarch/Documentation/kernel-parameters.txt	2009-06-24 14:25:32.000000000 -0400

@@ -1811,6 +1811,9 @@ and is between 256 and 4096 characters. 

 		check_enable_amd_mmconf [X86] check for and enable

 				properly configured MMIO access to PCI

 				config space on AMD family 10h CPU

+		msi		[MSI] If the PCI_MSI kernel config parameter is

+				enabled, this kernel boot option can be used to

+				enable the use of MSI interrupts system-wide.

 		nomsi		[MSI] If the PCI_MSI kernel config parameter is

 				enabled, this kernel boot option can be used to

 				disable the use of MSI interrupts system-wide.

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig

index 2a4501d..209758c 100644

--- a/drivers/pci/Kconfig

+++ b/drivers/pci/Kconfig

@@ -21,6 +21,18 @@ config PCI_MSI

 	   If you don't know what to do here, say N.

+config PCI_MSI_DEFAULT_ON

+	def_bool y

+	prompt "Use Message Signaled Interrupts by default"

+	depends on PCI_MSI

+	help

+	  Selecting this option will enable use of PCI MSI where applicable

+	  by default. Support for MSI can be disabled through the use of the

+	  pci=nomsi boot flag. Conversely, if this option is not selected,

+	  support for PCI MSI can be enabled by passing the pci=msi flag.

+

+	  If you don't know what to do here, say N.

+

 config PCI_LEGACY

 	bool "Enable deprecated pci_find_* API"

 	depends on PCI

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c

index 896a15d..53df583 100644

--- a/drivers/pci/msi.c

+++ b/drivers/pci/msi.c

@@ -23,7 +23,11 @@

 #include "pci.h"

 #include "msi.h"

+#ifdef CONFIG_PCI_MSI_DEFAULT_ON

 static int pci_msi_enable = 1;

+#else

+static int pci_msi_enable = 0;

+#endif /*CONFIG_PCI_MSI_DEFAULT_ON*/

 /* Arch hooks */

@@ -786,6 +790,11 @@ int pci_msi_enabled(void)

 }

 EXPORT_SYMBOL(pci_msi_enabled);

+void pci_yes_msi(void)

+{

+	pci_msi_enable = 1;

+}

+

 void pci_msi_init_pci_dev(struct pci_dev *dev)

 {

 	INIT_LIST_HEAD(&dev->msi_list);

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c

index 17bd932..e9bc9fe 100644

--- a/drivers/pci/pci.c

+++ b/drivers/pci/pci.c

@@ -2393,6 +2393,8 @@ static int __init pci_setup(char *str)

 		if (*str && (str = pcibios_setup(str)) && *str) {

 			if (!strcmp(str, "nomsi")) {

 				pci_no_msi();

+			} else if (!strcmp(str, "msi")) {

+				pci_yes_msi();

 			} else if (!strcmp(str, "noaer")) {

 				pci_no_aer();

 			} else if (!strcmp(str, "nodomains")) {

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h

index 26ddf78..85efe81 100644

--- a/drivers/pci/pci.h

+++ b/drivers/pci/pci.h

@@ -111,9 +111,11 @@ extern unsigned int pci_pm_d3_delay;

 #ifdef CONFIG_PCI_MSI

 void pci_no_msi(void);

+void pci_yes_msi(void);

 extern void pci_msi_init_pci_dev(struct pci_dev *dev);

 #else

 static inline void pci_no_msi(void) { }

+static inline void pci_yes_msi(void) { }

 static inline void pci_msi_init_pci_dev(struct pci_dev *dev) { }

 #endif