[PATCH] PCI: handle bogus MCFG entries

Handle more bogus MCFG entries

Some Asus P4 boards seem to have broken MCFG tables with
only a single entry for busses 0-0.  Special case these
and assume they mean all busses can be accessed.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 14 insertions, 5 deletions

diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c
index f16c0d57c552..00d4ddbf980c 100644
--- a/arch/x86_64/pci/mmconfig.c
+++ b/arch/x86_64/pci/mmconfig.c
@@ -29,11 +29,8 @@ static char __iomem *get_virt(unsigned int seg, unsigned bus)
 
         while (1) {
                 ++cfg_num;
-                if (cfg_num >= pci_mmcfg_config_num) {
-                        /* Not found - fall back to type 1. This happens
-                           e.g. on the internal devices of a K8 northbridge. */
-                        return NULL;
-                }
+                if (cfg_num >= pci_mmcfg_config_num)
+                        break;
                 cfg = pci_mmcfg_virt[cfg_num].cfg;
                 if (cfg->pci_segment_group_number != seg)
                         continue;
@@ -41,6 +38,18 @@ static char __iomem *get_virt(unsigned int seg, unsigned bus)
                     (cfg->end_bus_number >= bus))
                         return pci_mmcfg_virt[cfg_num].virt;
         }
+
+        /* Handle more broken MCFG tables on Asus etc.
+           They only contain a single entry for bus 0-0. Assume
+           this applies to all busses. */
+        cfg = &pci_mmcfg_config[0];
+        if (pci_mmcfg_config_num == 1 &&
+                cfg->pci_segment_group_number == 0 &&
+                (cfg->start_bus_number | cfg->end_bus_number) == 0)
+                return cfg->base_address;
+
+        /* Fall back to type 0 */
+        return 0;
 }
 
 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)