[PATCH] suspend: PCI power managment reference implementation

Added reference implementation of suspend and resume routines.

From: Shaohua Li <shaohua.li@intel.com>

  build fix

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/Documentation/power/pci.txt b/Documentation/power/pci.txt
index 35b1a7dae34253751ade84ca7f0eda948fac11dd..6fc9d511fc39ef01af4b88492b4b2edea5ffb623 100644 (file)
--- a/Documentation/power/pci.txt
+++ b/Documentation/power/pci.txt
@@ -291,6 +291,44 @@ 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 deriver specific operations in it, but drivers should do something like
+this on the whole.
+
 5. Resources
 ~~~~~~~~~~~~