centos man page for parport_yield

PARPORT_YIELD(9)					       Parallel Port Devices						  PARPORT_YIELD(9)

NAME
       parport_yield - relinquish a parallel port temporarily

SYNOPSIS
       int parport_yield(struct pardevice * dev);

ARGUMENTS
       dev
	   a device on the parallel port

DESCRIPTION
       This function relinquishes the port if it would be helpful to other drivers to do so. Afterwards it tries to reclaim the port using
       parport_claim, and the return value is the same as for parport_claim. If it fails, the port is left unclaimed and it is the driver's
       responsibility to reclaim the port.

       The parport_yield and parport_yield_blocking functions are for marking points in the driver at which other drivers may claim the port and
       use their devices. Yielding the port is similar to releasing it and reclaiming it, but is more efficient because no action is taken if
       there are no other devices needing the port. In fact, nothing is done even if there are other devices waiting but the current device is
       still within its "timeslice". The default timeslice is half a second, but it can be adjusted via the /proc interface.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							  PARPORT_YIELD(9)