1 files changed, 6 insertions, 3 deletions

diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c
index 6b1ea0c9a570..e545b0992c48 100644
--- a/arch/i386/pci/mmconfig.c
+++ b/arch/i386/pci/mmconfig.c
@@ -15,7 +15,9 @@
 #include <asm/e820.h>
 #include "pci.h"
 
-#define MMCONFIG_APER_SIZE (256*1024*1024)
+/* aperture is up to 256MB but BIOS may reserve less */
+#define MMCONFIG_APER_MIN       (2 * 1024*1024)
+#define MMCONFIG_APER_MAX       (256 * 1024*1024)
 
 /* Assume systems with more busses have correct MCFG */
 #define MAX_CHECK_BUS 16
@@ -197,9 +199,10 @@ void __init pci_mmcfg_init(void)
                 return;
 
         if (!e820_all_mapped(pci_mmcfg_config[0].base_address,
-                        pci_mmcfg_config[0].base_address + MMCONFIG_APER_SIZE,
+                        pci_mmcfg_config[0].base_address + MMCONFIG_APER_MIN,
                         E820_RESERVED)) {
-                printk(KERN_ERR "PCI: BIOS Bug: MCFG area is not E820-reserved\n");
+                printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n",
+                                pci_mmcfg_config[0].base_address);
                 printk(KERN_ERR "PCI: Not using MMCONFIG.\n");
                 return;
         }