suspend/resume PM criterion for application

[Ran Shalit]

Hello,

What is usually the criterion for PM (power management) suspending
that application shall use ? Is it according to minimum threshold for
cpu load (as indication for no process) ?

How usually it is performed, i.e.  is it some periodic process, which
wakes up periodically to check criterion for cpu load ? If so, isn't
it problematic in PM terms, becuase it mean that the system is resumed
periodically (as a result of the the periodic timer's interrupt), and
all devices are resumed ?

Thanks,
Ran