The power management protocol supports power cycles that are transparent to applications.
Block Drivers that can be managed by Power Manager should advertise the PMCLASS_BLOCK_DEVICE interface. If a block driver does not advertise the PMCLASS_BLOCK_DEVICE interface, the device might hang during suspend. For more information, see Device Interfaces.
It is important that block device drivers handle the POWER_DOWN and POWER_UP system messages efficiently.
Like all device drivers, block device drivers must limit themselves to minimal, very fast processing of the POWER_DOWN message. To accomplish this, they should save any volatile state information in RAM, set a flag to indicate that power is about to turn off, and then exit.
POWER_ON processing is exactly like the processing for a regular card removal that follows an insertion.
Next, it checks the socket status and issues card-insertion notices for each socket with a card.
Then, the Device Manager launches its detection sequence and loads the appropriate driver for each card. For more information about the Device Manager, see Device Manager.
See Also
Device Interfaces | Block Driver Architecture | Block Driver Samples | Block Driver Registry Settings | Block Driver Manager | Block Device File Systems | File System Loading and Unloading | Block Driver Interface | Block Driver Loading | Block Driver Installation | Block Driver Detection | Block Driver Access
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