diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 9fe026b1c9d02f2893b0192a7650703dfeeac03b..5b38a026d1220113aec9c88cbb08f325537012d3 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -350,6 +350,8 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	if (pcie_aspm_enabled())
 		flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
 			OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
+	if (pci_msi_enabled())
+		flags |= OSC_MSI_SUPPORT;
 	if (flags != base_flags)
 		pci_acpi_osc_support(device->handle, flags);
 
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 11a51f8ed3b3b96ffa72820f195c6a7afa4bfa40..b4a90badd0a6d66c57c83961f8bc956a49aa7d7a 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -776,28 +776,19 @@ void pci_no_msi(void)
 	pci_msi_enable = 0;
 }
 
-void pci_msi_init_pci_dev(struct pci_dev *dev)
-{
-	INIT_LIST_HEAD(&dev->msi_list);
-}
-
-#ifdef CONFIG_ACPI
-#include <linux/acpi.h>
-#include <linux/pci-acpi.h>
-static void __devinit msi_acpi_init(void)
+/**
+ * pci_msi_enabled - is MSI enabled?
+ *
+ * Returns true if MSI has not been disabled by the command-line option
+ * pci=nomsi.
+ **/
+int pci_msi_enabled(void)
 {
-	if (acpi_pci_disabled)
-		return;
-	pci_osc_support_set(OSC_MSI_SUPPORT);
-	pcie_osc_support_set(OSC_MSI_SUPPORT);
+	return pci_msi_enable;
 }
-#else
-static inline void msi_acpi_init(void) { }
-#endif /* CONFIG_ACPI */
+EXPORT_SYMBOL(pci_msi_enabled);
 
-void __devinit msi_init(void)
+void pci_msi_init_pci_dev(struct pci_dev *dev)
 {
-	if (!pci_msi_enable)
-		return;
-	msi_acpi_init();
+	INIT_LIST_HEAD(&dev->msi_list);
 }
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 48fa860276d4adbf6ca28f317a1db8e4dbad9c9a..2cfa41e367a78a63ead49905dbf2583f087e496e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2105,8 +2105,6 @@ static int __devinit pci_init(void)
 		pci_fixup_device(pci_fixup_final, dev);
 	}
 
-	msi_init();
-
 	return 0;
 }
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index d3e65e29df5113e94c9669c239b49a403c059be6..9162e242b99ee3178cfb5c17726f885a1c0428fc 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -102,11 +102,9 @@ extern unsigned int pci_pm_d3_delay;
 #ifdef CONFIG_PCI_MSI
 void pci_no_msi(void);
 extern void pci_msi_init_pci_dev(struct pci_dev *dev);
-extern void __devinit msi_init(void);
 #else
 static inline void pci_no_msi(void) { }
 static inline void pci_msi_init_pci_dev(struct pci_dev *dev) { }
-static inline void msi_init(void) { }
 #endif
 
 #ifdef CONFIG_PCIEAER
diff --git a/include/linux/pci.h b/include/linux/pci.h
index eae97a2bf6038c7a195287b6e9f2745d0719a074..59a3dc2059d3c818dee1c7b7a1c5e7790c459fbb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -779,6 +779,10 @@ static inline void msi_remove_pci_irq_vectors(struct pci_dev *dev)
 
 static inline void pci_restore_msi_state(struct pci_dev *dev)
 { }
+static inline int pci_msi_enabled(void)
+{
+	return 0;
+}
 #else
 extern int pci_enable_msi(struct pci_dev *dev);
 extern void pci_msi_shutdown(struct pci_dev *dev);
@@ -789,6 +793,7 @@ extern void pci_msix_shutdown(struct pci_dev *dev);
 extern void pci_disable_msix(struct pci_dev *dev);
 extern void msi_remove_pci_irq_vectors(struct pci_dev *dev);
 extern void pci_restore_msi_state(struct pci_dev *dev);
+extern int pci_msi_enabled(void);
 #endif
 
 #ifndef CONFIG_PCIEASPM