'\" t
.\"     Title: parport_wait_peripheral
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: May 2018
.\"    Manual: Parallel Port Devices
.\"    Source: Kernel Hackers Manual 3.16.56
.\"  Language: English
.\"
.TH "PARPORT_WAIT_PERIPHE" "9" "May 2018" "Kernel Hackers Manual 3\&.16\&" "Parallel Port Devices"
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.SH "NAME"
parport_wait_peripheral \- wait for status lines to change in 35ms
.SH "SYNOPSIS"
.HP \w'int\ parport_wait_peripheral('u
.BI "int parport_wait_peripheral(struct\ parport\ *\ " "port" ", unsigned\ char\ " "mask" ", unsigned\ char\ " "result" ");"
.SH "ARGUMENTS"
.PP
\fIport\fR
.RS 4
port to watch
.RE
.PP
\fImask\fR
.RS 4
status lines to watch
.RE
.PP
\fIresult\fR
.RS 4
desired values of chosen status lines
.RE
.SH "DESCRIPTION"
.PP
This function waits until the masked status lines have the desired values, or until 35ms have elapsed (see IEEE 1284\-1994 page 24 to 25 for why this value in particular is hardcoded)\&. The
\fImask\fR
and
\fIresult\fR
parameters are bitmasks, with the bits defined by the constants in parport\&.h:
\fBPARPORT_STATUS_BUSY\fR, and so on\&.
.PP
The port is polled quickly to start off with, in anticipation of a fast response from the peripheral\&. This fast polling time is configurable (using /proc), and defaults to 500usec\&. If the timeout for this port (see
\fBparport_set_timeout\fR) is zero, the fast polling time is 35ms, and this function does not call
\fBschedule\fR\&.
.PP
If the timeout for this port is non\-zero, after the fast polling fails it uses
\fBparport_wait_event\fR
to wait for up to 10ms, waking up if an interrupt occurs\&.
.SH "COPYRIGHT"
.br