[AGPGART] Suspend/Resume support for nVidia nForce AGP.

Based on a patch from the Ubuntu kernel.
Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

drivers/char/agp/nvidia-agp.c

@@ -375,6 +375,31 @@ static void __devexit agp_nvidia_remove(struct pci_dev *pdev)
 	agp_put_bridge(bridge);
 }
 
+#ifdef CONFIG_PM
+static int agp_nvidia_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+	pci_save_state (pdev);
+	pci_set_power_state (pdev, 3);
+
+	return 0;
+}
+
+static int agp_nvidia_resume(struct pci_dev *pdev)
+{
+	struct agp_bridge_data *bridge = pci_get_drvdata(pdev);
+
+	/* set power state 0 and restore PCI space */
+	pci_set_power_state (pdev, 0);
+	pci_restore_state(pdev);
+
+	/* reconfigure AGP hardware again */
+	nvidia_configure();
+
+	return 0;
+}
+#endif
+
+
 static struct pci_device_id agp_nvidia_pci_table[] = {
 	{
 	.class		= (PCI_CLASS_BRIDGE_HOST << 8),
@@ -402,6 +427,10 @@ static struct pci_driver agp_nvidia_pci_driver = {
 	.id_table	= agp_nvidia_pci_table,
 	.probe		= agp_nvidia_probe,
 	.remove		= agp_nvidia_remove,
+#ifdef CONFIG_PM
+	.suspend	= agp_nvidia_suspend,
+	.resume		= agp_nvidia_resume,
+#endif
 };
 
 static int __init agp_nvidia_init(void)