These functions are intended for use by individual drivers, and are defined in
struct pci_driver:
- int (*save_state) (struct pci_dev *dev, u32 state);
- int (*suspend) (struct pci_dev *dev, u32 state);
+ int (*suspend) (struct pci_dev *dev, pm_message_t state);
int (*resume) (struct pci_dev *dev);
- int (*enable_wake) (struct pci_dev *dev, u32 state, int enable);
-
-
-save_state
-----------
-
-Usage:
-
-if (dev->driver && dev->driver->save_state)
- dev->driver->save_state(dev,state);
-
-The driver should use this callback to save device state. It should take into
-account the current state of the device and the requested state in order to
-avoid any unnecessary operations.
-
-For example, a video card that supports all 4 states (D0-D3), all controller
-context is preserved when entering D1, but the screen is placed into a low power
-state (blanked).
-
-The driver can also interpret this function as a notification that it may be
-entering a sleep state in the near future. If it knows that the device cannot
-enter the requested state, either because of lack of support for it, or because
-the device is middle of some critical operation, then it should fail.
-
-This function should not be used to set any state in the device or the driver
-because the device may not actually enter the sleep state (e.g. another driver
-later causes causes a global state transition to fail).
-
-Note that in intermediate low power states, a device's I/O and memory spaces may
-be disabled and may not be available in subsequent transitions to lower power
-states.
+ int (*enable_wake) (struct pci_dev *dev, pci_power_t state, int enable);
suspend
pci_enable_wake (one for both D3hot and D3cold).
+A reference implementation
+-------------------------
+.suspend()
+{
+ /* driver specific operations */
+
+ /* Disable IRQ */
+ free_irq();
+ /* If using MSI */
+ pci_disable_msi();
+
+ pci_save_state();
+ pci_enable_wake();
+ /* Disable IO/bus master/irq router */
+ pci_disable_device();
+ pci_set_power_state(pci_choose_state());
+}
+
+.resume()
+{
+ pci_set_power_state(PCI_D0);
+ pci_restore_state();
+ /* device's irq possibly is changed, driver should take care */
+ pci_enable_device();
+ pci_set_master();
+
+ /* if using MSI, device's vector possibly is changed */
+ pci_enable_msi();
+
+ request_irq();
+ /* driver specific operations; */
+}
+
+This is a typical implementation. Drivers can slightly change the order
+of the operations in the implementation, ignore some operations or add
+more deriver specific operations in it, but drivers should do something like
+this on the whole.
+
5. Resources
~~~~~~~~~~~~
PCI Local Bus Specification
PCI Bus Power Management Interface Specification
- http://pcisig.org
+ http://www.pcisig.com