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Diffstat (limited to 'Documentation/power/devices.txt')
| -rw-r--r-- | Documentation/power/devices.txt | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt index 1971bcf48a6..88880839ece 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 |