Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
pm_send_all - send request to all managed devices
SYNOPSIS
int pm_send_all (pm_request_t rqst, void * data);
ARGUMENTS
rqst power management request
data data for the callback
DESCRIPTION
Issue a power management request to a all devices. The PM_SUSPEND
events are handled specially. Any device is permitted to fail a suspend
by returning a non zero (error) value from its callback function. If
any device vetoes a suspend request then all other devices that have
suspended during the processing of this request are restored to their
previous state.
WARNING
This function takes the pm_devs_lock. The lock is not dropped until the
callbacks have completed. This prevents races against pm locking
functions, races against module unload pm_unregister code. It does mean
however that you must not issue pm_ functions within the callback or
you will deadlock and users will hate you.
Zero is returned on success. If a suspend fails then the status from
the device that vetoes the suspend is returned.
BUGS
what stops two power management requests occurring in parallel and
conflicting.