[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>

1 files changed, 38 insertions, 0 deletions

diff --git a/Documentation/power/pci.txt b/Documentation/power/pci.txt
index 35b1a7dae34..6fc9d511fc3 100644
--- 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
 ~~~~~~~~~~~~