diff --git a/drivers/char/agp/amd-k7-agp.c b/drivers/char/agp/amd-k7-agp.c
index 5f028cb..3661a51 100644
--- a/drivers/char/agp/amd-k7-agp.c
+++ b/drivers/char/agp/amd-k7-agp.c
@@ -11,7 +11,7 @@
 #include <linux/slab.h>
 #include "agp.h"
 
-#define AMD_MMBASE	0x14
+#define AMD_MMBASE_BAR	1
 #define AMD_APSIZE	0xac
 #define AMD_MODECNTL	0xb0
 #define AMD_MODECNTL2	0xb2
@@ -205,6 +205,7 @@
 static int amd_irongate_configure(void)
 {
 	struct aper_size_info_lvl2 *current_size;
+	phys_addr_t reg;
 	u32 temp;
 	u16 enable_reg;
 
@@ -212,9 +213,8 @@
 
 	if (!amd_irongate_private.registers) {
 		/* Get the memory mapped registers */
-		pci_read_config_dword(agp_bridge->dev, AMD_MMBASE, &temp);
-		temp = (temp & PCI_BASE_ADDRESS_MEM_MASK);
-		amd_irongate_private.registers = (volatile u8 __iomem *) ioremap(temp, 4096);
+		reg = pci_resource_start(agp_bridge->dev, AMD_MMBASE_BAR);
+		amd_irongate_private.registers = (volatile u8 __iomem *) ioremap(reg, 4096);
 		if (!amd_irongate_private.registers)
 			return -ENOMEM;
 	}
diff --git a/drivers/char/agp/ati-agp.c b/drivers/char/agp/ati-agp.c
index 53cb310..ba83c11 100644
--- a/drivers/char/agp/ati-agp.c
+++ b/drivers/char/agp/ati-agp.c
@@ -12,7 +12,7 @@
 #include <asm/agp.h>
 #include "agp.h"
 
-#define ATI_GART_MMBASE_ADDR	0x14
+#define ATI_GART_MMBASE_BAR	1
 #define ATI_RS100_APSIZE	0xac
 #define ATI_RS100_IG_AGPMODE	0xb0
 #define ATI_RS300_APSIZE	0xf8
@@ -196,12 +196,12 @@
 
 static int ati_configure(void)
 {
+	phys_addr_t reg;
 	u32 temp;
 
 	/* Get the memory mapped registers */
-	pci_read_config_dword(agp_bridge->dev, ATI_GART_MMBASE_ADDR, &temp);
-	temp = (temp & 0xfffff000);
-	ati_generic_private.registers = (volatile u8 __iomem *) ioremap(temp, 4096);
+	reg = pci_resource_start(agp_bridge->dev, ATI_GART_MMBASE_BAR);
+	ati_generic_private.registers = (volatile u8 __iomem *) ioremap(reg, 4096);
 
 	if (!ati_generic_private.registers)
 		return -ENOMEM;
diff --git a/drivers/char/agp/nvidia-agp.c b/drivers/char/agp/nvidia-agp.c
index ab65d55..a1861b7 100644
--- a/drivers/char/agp/nvidia-agp.c
+++ b/drivers/char/agp/nvidia-agp.c
@@ -106,6 +106,7 @@
 {
 	int i, rc, num_dirs;
 	u32 apbase, aplimit;
+	phys_addr_t apbase_phys;
 	struct aper_size_info_8 *current_size;
 	u32 temp;
 
@@ -152,8 +153,9 @@
 	pci_write_config_dword(agp_bridge->dev, NVIDIA_0_APSIZE, temp | 0x100);
 
 	/* map aperture */
+	apbase_phys = pci_resource_start(agp_bridge->dev, AGP_APERTURE_BAR);
 	nvidia_private.aperture =
-		(volatile u32 __iomem *) ioremap(apbase, 33 * PAGE_SIZE);
+		(volatile u32 __iomem *) ioremap(apbase_phys, 33 * PAGE_SIZE);
 
 	if (!nvidia_private.aperture)
 		return -ENOMEM;