'\" t
.\"     Title: parport_yield
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: Parallel Port Devices
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "PARPORT_YIELD" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Parallel Port Devices"
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.SH "NAME"
parport_yield \- relinquish a parallel port temporarily
.SH "SYNOPSIS"
.HP \w'int\ parport_yield('u
.BI "int parport_yield(struct\ pardevice\ *\ " "dev" ");"
.SH "ARGUMENTS"
.PP
\fIdev\fR
.RS 4
a device on the parallel port
.RE
.SH "DESCRIPTION"
.PP
This function relinquishes the port if it would be helpful to other drivers to do so\&. Afterwards it tries to reclaim the port using
\fBparport_claim\fR, and the return value is the same as for
\fBparport_claim\fR\&. If it fails, the port is left unclaimed and it is the driver\*(Aqs responsibility to reclaim the port\&.
.PP
The
\fBparport_yield\fR
and
\fBparport_yield_blocking\fR
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
\(lqtimeslice\(rq\&. The default timeslice is half a second, but it can be adjusted via the /proc interface\&.
.SH "COPYRIGHT"
.br