OS X and iOS Kernel Programming

Summary

• Every computer that runs Mac OS X has the ability to be placed in a low power mode known as “sleep”. While in sleep mode, most hardware components are either powered down completely or are provided with only a reduced current.
• A device driver can register and respond to requests from the power management system to prepare its hardware for a loss of power before sleep and to restore the state of its hardware when the system is woken from sleep.
• The I/O Kit's power management API is implemented by the IOService base class. This makes it possible for every driver to provide support for power management.
• A driver may opt to lower the power state of its device independently of whether the computer is in the sleep mode. This can be useful ...