ACPI: Disable MSI on request of FADT

The ACPI spec defines the bit and Microsoft uses it,
so Linux must use it too.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 5 insertions, 0 deletions

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index a064f36a0805..b5ac810404c0 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -317,6 +317,10 @@ static int __init acpi_pci_init(void)
 {
         int ret;
 
+        if (acpi_gbl_FADT.boot_flags & BAF_MSI_NOT_SUPPORTED) {
+                printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it\n");
+                pci_no_msi();
+        }
         ret = register_acpi_bus_type(&acpi_pci_bus);
         if (ret)
                 return 0;
diff --git a/include/acpi/actbl.h b/include/acpi/actbl.h
index 09469e7db6a5..955adfb8d64c 100644
--- a/include/acpi/actbl.h
+++ b/include/acpi/actbl.h
@@ -276,6 +276,7 @@ enum acpi_prefered_pm_profiles {
 
 #define BAF_LEGACY_DEVICES              0x0001
 #define BAF_8042_KEYBOARD_CONTROLLER    0x0002
+#define BAF_MSI_NOT_SUPPORTED           0x0008
 
 #define FADT2_REVISION_ID               3
 #define FADT2_MINUS_REVISION_ID         2