1 files changed, 9 insertions, 5 deletions

diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 1971bcf48a60..88880839ece4 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -279,11 +279,15 @@ When the system goes into the standby or memory sleep state, the phases are:
         time.)  Unlike the other suspend-related phases, during the prepare
         phase the device tree is traversed top-down.
 
-        The prepare phase uses only a bus callback.  After the callback method
-        returns, no new children may be registered below the device.  The method
-        may also prepare the device or driver in some way for the upcoming
-        system power transition, but it should not put the device into a
-        low-power state.
+        In addition to that, if device drivers need to allocate additional
+        memory to be able to hadle device suspend correctly, that should be
+        done in the prepare phase.
+
+        After the prepare callback method returns, no new children may be
+        registered below the device.  The method may also prepare the device or
+        driver in some way for the upcoming system power transition (for
+        example, by allocating additional memory required for this purpose), but
+        it should not put the device into a low-power state.
 
     2.  The suspend methods should quiesce the device to stop it from performing
         I/O.  They also may save the device registers and put it into the