blk_pm_runtime_init — Block layer runtime PM initialization routine
|struct request_queue * q,|
|struct device * dev|
Initialize runtime-PM-related fields for
q and start auto suspend for
dev. Drivers that want to take advantage of request-based runtime PM
should call this function after
dev has been initialized, and its
q has been allocated, and runtime PM for it can not happen
yet(either due to disabled/forbidden or its usage_count > 0). In most
cases, driver should call this function before any I/O has taken place.
This function takes care of setting up using auto suspend for the device, the autosuspend delay is set to -1 to make runtime suspend impossible until an updated value is either set by user or by driver. Drivers do not need to touch other autosuspend settings.
The block layer runtime PM is request based, so only works for drivers that use request as their IO unit instead of those directly use bio's.