fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / Documentation / power / pci.txt

diff --git a/Documentation/power/pci.txt b/Documentation/power/pci.txt
index c85428e..c750f9f 100644 (file)
--- a/Documentation/power/pci.txt
+++ b/Documentation/power/pci.txt
@@ -153,7 +153,7 @@ Description:
        events, which is implicit if it doesn't even support it in the first
        place).
 
-       Note that the PMC Register in the device's PM Capabilties has a bitmask
+       Note that the PMC Register in the device's PM Capabilities has a bitmask
        of the states it supports generating PME# from. D3hot is bit 3 and
        D3cold is bit 4. So, while a value of 4 as the state may not seem
        semantically correct, it is. 
@@ -165,40 +165,9 @@ Description:
 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
@@ -299,7 +268,7 @@ to wake the system up. (However, it is possible that a device may support
 some non-standard way of generating a wake event on sleep.)
 
 Bits 15:11 of the PMC (Power Mgmt Capabilities) Register in a device's
-PM Capabilties describe what power states the device supports generating a 
+PM Capabilities describe what power states the device supports generating a 
 wake event from:
 
 +------------------+
@@ -322,11 +291,49 @@ a request to enable wake events from D3, two calls should be made to
 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 driver 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