diff --git a/drivers/char/agp/amd-k7-agp.c b/drivers/char/agp/amd-k7-agp.c
index 603a986e96af..3f98254b911f 100644
--- a/drivers/char/agp/amd-k7-agp.c
+++ b/drivers/char/agp/amd-k7-agp.c
@@ -223,12 +223,14 @@ static int amd_irongate_configure(void)
 
 	current_size = A_SIZE_LVL2(agp_bridge->current_size);
 
-	/* 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);
-	if (!amd_irongate_private.registers)
-		return -ENOMEM;
+	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);
+		if (!amd_irongate_private.registers)
+			return -ENOMEM;
+	}
 
 	/* Write out the address of the gatt table */
 	writel(agp_bridge->gatt_bus_addr, amd_irongate_private.registers+AMD_ATTBASE);
@@ -492,6 +494,26 @@ static void __devexit agp_amdk7_remove(struct pci_dev *pdev)
 	agp_put_bridge(bridge);
 }
 
+#ifdef CONFIG_PM
+
+static int agp_amdk7_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+	pci_save_state(pdev);
+	pci_set_power_state(pdev, pci_choose_state(pdev, state));
+
+	return 0;
+}
+
+static int agp_amdk7_resume(struct pci_dev *pdev)
+{
+	pci_set_power_state(pdev, PCI_D0);
+	pci_restore_state(pdev);
+
+	return amd_irongate_driver.configure();
+}
+
+#endif /* CONFIG_PM */
+
 /* must be the same order as name table above */
 static struct pci_device_id agp_amdk7_pci_table[] = {
 	{
@@ -528,6 +550,10 @@ static struct pci_driver agp_amdk7_pci_driver = {
 	.id_table	= agp_amdk7_pci_table,
 	.probe		= agp_amdk7_probe,
 	.remove		= agp_amdk7_remove,
+#ifdef CONFIG_PM
+	.suspend	= agp_amdk7_suspend,
+	.resume		= agp_amdk7_resume,
+#endif
 };
 
 static int __init agp_amdk7_init(void)
diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index 043e36628d6d..1108665913e2 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -54,8 +54,7 @@
 		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965Q_HB || \
 		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965G_HB || \
 		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965GM_HB || \
-		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965GME_HB || \
-		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_GM45_HB)
+		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965GME_HB)
 
 #define IS_G33 (agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_G33_HB || \
 		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_Q35_HB || \
@@ -63,7 +62,8 @@
 
 #define IS_G4X (agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_IGD_E_HB || \
 		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_Q45_HB || \
-		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_G45_HB)
+		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_G45_HB || \
+		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_GM45_HB)
 
 extern int agp_memory_reserved;
 
@@ -214,8 +214,8 @@ static int intel_i810_configure(void)
 	if (agp_bridge->driver->needs_scratch_page) {
 		for (i = 0; i < current_size->num_entries; i++) {
 			writel(agp_bridge->scratch_page, intel_private.registers+I810_PTE_BASE+(i*4));
-			readl(intel_private.registers+I810_PTE_BASE+(i*4));	/* PCI posting. */
 		}
+		readl(intel_private.registers+I810_PTE_BASE+((i-1)*4));	/* PCI posting. */
 	}
 	global_cache_flush();
 	return 0;
@@ -525,8 +525,10 @@ static void intel_i830_init_gtt_entries(void)
 		size += 4;
 	} else if (IS_G4X) {
 		/* On 4 series hardware, GTT stolen is separate from graphics
-		 * stolen, ignore it in stolen gtt entries counting */
-		size = 0;
+		 * stolen, ignore it in stolen gtt entries counting.  However,
+		 * 4KB of the stolen memory doesn't get mapped to the GTT.
+		 */
+		size = 4;
 	} else {
 		/* On previous hardware, the GTT size was just what was
 		 * required to map the aperture.
@@ -773,8 +775,8 @@ static int intel_i830_configure(void)
 	if (agp_bridge->driver->needs_scratch_page) {
 		for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) {
 			writel(agp_bridge->scratch_page, intel_private.registers+I810_PTE_BASE+(i*4));
-			readl(intel_private.registers+I810_PTE_BASE+(i*4));	/* PCI Posting. */
 		}
+		readl(intel_private.registers+I810_PTE_BASE+((i-1)*4));	/* PCI Posting. */
 	}
 
 	global_cache_flush();
@@ -989,8 +991,8 @@ static int intel_i915_configure(void)
 	if (agp_bridge->driver->needs_scratch_page) {
 		for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) {
 			writel(agp_bridge->scratch_page, intel_private.gtt+i);
-			readl(intel_private.gtt+i);	/* PCI Posting. */
 		}
+		readl(intel_private.gtt+i-1);	/* PCI Posting. */
 	}
 
 	global_cache_flush();
diff --git a/drivers/char/agp/nvidia-agp.c b/drivers/char/agp/nvidia-agp.c
index dc70d3771811..5bbed3d79db9 100644
--- a/drivers/char/agp/nvidia-agp.c
+++ b/drivers/char/agp/nvidia-agp.c
@@ -201,10 +201,15 @@ extern int agp_memory_reserved;
 static int nvidia_insert_memory(struct agp_memory *mem, off_t pg_start, int type)
 {
 	int i, j;
+	int mask_type;
 
-	if ((type != 0) || (mem->type != 0))
+	mask_type = agp_generic_type_to_mask_type(mem->bridge, type);
+	if (mask_type != 0 || type != mem->type)
 		return -EINVAL;
 
+	if (mem->page_count == 0)
+		return 0;
+
 	if ((pg_start + mem->page_count) >
 		(nvidia_private.num_active_entries - agp_memory_reserved/PAGE_SIZE))
 		return -EINVAL;
@@ -220,10 +225,13 @@ static int nvidia_insert_memory(struct agp_memory *mem, off_t pg_start, int type
 	}
 	for (i = 0, j = pg_start; i < mem->page_count; i++, j++) {
 		writel(agp_bridge->driver->mask_memory(agp_bridge,
-			mem->memory[i], mem->type),
+			mem->memory[i], mask_type),
 			agp_bridge->gatt_table+nvidia_private.pg_offset+j);
-		readl(agp_bridge->gatt_table+nvidia_private.pg_offset+j);	/* PCI Posting. */
 	}
+
+	/* PCI Posting. */
+	readl(agp_bridge->gatt_table+nvidia_private.pg_offset+j - 1);
+
 	agp_bridge->driver->tlb_flush(mem);
 	return 0;
 }
@@ -233,9 +241,15 @@ static int nvidia_remove_memory(struct agp_memory *mem, off_t pg_start, int type
 {
 	int i;
 
-	if ((type != 0) || (mem->type != 0))
+	int mask_type;
+
+	mask_type = agp_generic_type_to_mask_type(mem->bridge, type);
+	if (mask_type != 0 || type != mem->type)
 		return -EINVAL;
 
+	if (mem->page_count == 0)
+		return 0;
+
 	for (i = pg_start; i < (mem->page_count + pg_start); i++)
 		writel(agp_bridge->scratch_page, agp_bridge->gatt_table+nvidia_private.pg_offset+i);