From 85e952c63d5258642d864ef91de554e001d97c06 Mon Sep 17 00:00:00 2001
From: Sean Young <sean@mess.org>
Date: Wed, 31 Oct 2018 23:18:01 +0000
Subject: [PATCH] lirc.4: Unsupported ioctl() operationsalways return ENOTTY

Note that LIRC_GET_FEATURES is the only ioctl() which is always
supported now that there are send-only devices.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man4/lirc.4 | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/man4/lirc.4 b/man4/lirc.4
index 58ea1193c..a8463a4a8 100644
--- a/man4/lirc.4
+++ b/man4/lirc.4
@@ -55,8 +55,9 @@ of hardware can also be used in
 mode, in which case the kernel IR decoders will decode the IR. These
 decoders can be written in bpf(2) and attached to the lirc device.
 .PP
-The \fBLIRC_GET_REC_MODE\fR ioctl (see below) allows probing for the
-mode.
+The \fBLIRC_GET_FEATURES\fR ioctl (see below) allows probing for whether
+receiving and sending is supported, and in which modes, amongst other
+features.
 .\"
 .SS Reading input with the LIRC_MODE_MODE2 mode
 .PP
@@ -156,35 +157,31 @@ initially.
 .TP 4
 .BR LIRC_GET_FEATURES " (\fIvoid\fP)"
 Returns a bit mask of combined features bits; see FEATURES.
-Some drivers have dynamic features which are not updated until after an
-.I init()
-command.
+.PP
+If a device returns an error code for
+.BR LIRC_GET_FEATURES ,
+it is safe to assume it is not a lirc device.
+.\"
+.SS Optional Commands
+.PP
+Some lirc devices support commands listed below.
+Unless otherwise stated, these fail with the error \fBENOTTY\fR if the
+operation isn't supported, or with the error \fBEINVAL\fR if the operation
+failed, or invalid arguments were provided.
 If a driver does not announce support of certain features, calling of
-the corresponding ioctls is undefined.
+the corresponding ioctls will return ENOTTY.
 .TP
-.BR LIRC_GET_REC_MODE
+.BR LIRC_GET_REC_MODE " (\fIvoid\fP)"
 Return the receive mode, which will be one of:
 .RS 4
 .TP
-.BR LIRC_MODE_MODE2 " (\fIvoid\fP)"
+.BR LIRC_MODE_MODE2
 The driver returns a sequence of pulse/space durations.
 .TP
 .BR LIRC_MODE_SCANCODE
 The driver returns struct lirc_scancode values, each of which represents
 a decoded button press.
 .RE
-.PP
-If a device returns an error code for
-.BR LIRC_GET_REC_MODE ,
-it is safe to assume it is not a lirc device.
-.\"
-.SS Optional Commands
-.PP
-Some lirc devices support commands listed below.
-Unless otherwise stated, these fail with the error \fBENOIOCTLCMD\fR
-or with the error \fBENOSYS\fR if the operation
-isn't supported, or with the error \fBEINVAL\fR if the operation
-failed.
 .TP
 .BR LIRC_SET_REC_MODE " (\fIint\fP)"
 Set the receive mode.