diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 4edff17..d77c230 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -212,6 +212,12 @@
 		ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Device is not power manageable\n"));
 		return_VALUE(-ENODEV);
 	}
+	/*
+	 * Get device's current power state if it's unknown
+	 * This means device power state isn't initialized or previous setting failed
+	 */
+	if (device->power.state == ACPI_STATE_UNKNOWN)
+		acpi_bus_get_power(device->handle, &device->power.state);
 	if (state == device->power.state) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n", state));
 		return_VALUE(0);
@@ -231,7 +237,7 @@
 	 * On transitions to a high-powered state we first apply power (via
 	 * power resources) then evalute _PSx.  Conversly for transitions to
 	 * a lower-powered state.
-	 */ 
+	 */
 	if (state < device->power.state) {
 		if (device->power.flags.power_resources) {
 			result = acpi_power_transition(device, state);
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 8eb5997..a0d43ea 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -253,6 +253,24 @@
 	return -ENODEV;
 }
 
+static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
+{
+	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
+	static int state_conv[] = {
+		[0] = 0,
+		[1] = 1,
+		[2] = 2,
+		[3] = 3,
+		[4] = 3
+	};
+	int acpi_state = state_conv[(int __force) state];
+
+	if (!handle)
+		return -ENODEV;
+	return acpi_bus_set_power(handle, acpi_state);
+}
+
+
 /* ACPI bus type */
 static int pci_acpi_find_device(struct device *dev, acpi_handle *handle)
 {
@@ -300,6 +318,7 @@
 	if (ret)
 		return 0;
 	platform_pci_choose_state = acpi_pci_choose_state;
+	platform_pci_set_power_state = acpi_pci_set_power_state;
 	return 0;
 }
 arch_initcall(pci_acpi_init);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 5af9418..a1c66e8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -235,7 +235,7 @@
  * -EIO if device does not support PCI PM.
  * 0 if we can successfully change the power state.
  */
-
+int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t t) = NULL;
 int
 pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
@@ -299,8 +299,15 @@
 		msleep(10);
 	else if (state == PCI_D2 || dev->current_state == PCI_D2)
 		udelay(200);
-	dev->current_state = state;
 
+	/*
+	 * Give firmware a chance to be called, such as ACPI _PRx, _PSx
+	 * Firmware method after natice method ?
+	 */
+	if (platform_pci_set_power_state)
+		platform_pci_set_power_state(dev, state);
+
+	dev->current_state = state;
 	return 0;
 }
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 25c4492..d94d7af 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -13,6 +13,7 @@
 				  void *alignf_data);
 /* Firmware callbacks */
 extern int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
+extern int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t state);
 
 /* PCI /proc functions */
 #ifdef CONFIG_PROC_FS