LDP
/
man-pages
mirror of https://github.com/mkerrisk/man-pages
0
1
Fork 0
Code Releases Activity

lirc.4: Minor wording and formatting fixes 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2018-11-04 11:59:58 +01:00
parent aef83b6047
commit f3c3a5c42b
1 changed files with 25 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
man4/lirc.4
View File

@ -35,13 +35,13 @@ When receiving or sending data, the driver works in two different modes
depending on the underlying hardware.
.PP
Some hardware (typically TV-cards) decodes the IR signal internally
and provide decoded button presses as scancode values.
and provides decoded button presses as scancode values.
Drivers for this kind of hardware work in
.BR LIRC_MODE_SCANCODE
mode.
Such hardware usually does not support sending IR signals.
Furthermore, they can only decode a limited set of IR protocols, usually
only the protocol of the specific remote which is
Furthermore, such hardware can only decode a limited set of IR protocols,
usually only the protocol of the specific remote which is
bundled with, for example, a TV-card.
.PP
Other hardware provides a stream of pulse/space durations.
@ -70,20 +70,20 @@ In the \fBLIRC_MODE_MODE2 mode\fR, the data returned by
.BR read (2)
provides 32-bit values representing a space or a pulse duration.
The time of the duration (microseconds) is encoded in the lower 24 bits.
The upper 8 bit reflects the type of package:
The upper 8 bits indicate the type of package:
.TP 4
.BR LIRC_MODE2_SPACE .
.BR LIRC_MODE2_SPACE
Value reflects a space duration (microseconds).
.TP 4
.BR LIRC_MODE2_PULSE .
.BR LIRC_MODE2_PULSE
Value reflects a pulse duration (microseconds).
.TP 4
.BR LIRC_MODE2_FREQUENCY .
.BR LIRC_MODE2_FREQUENCY
Value reflects a frequency (Hz); see the
.B LIRC_SET_MEASURE_CARRIER_MODE
ioctl.
.TP 4
.BR LIRC_MODE2_TIMEOUT .
.BR LIRC_MODE2_TIMEOUT
Value reflects a space duration (microseconds).
The package reflects a timeout; see the
.B LIRC_SET_REC_TIMEOUT_REPORTS
@ -96,7 +96,7 @@ mode, the data returned by
.BR read (2)
reflects decoded button presses, in the struct \fIlirc_scancode\fR.
The scancode is stored in the \fIscancode\fR field, and the IR protocol
in \fIrc_proto\fR.
is stored in \fIrc_proto\fR.
This field has one the values of the \fIenum rc_proto\fR.
.\"
.SS Writing output with the LIRC_MODE_PULSE mode
@ -132,8 +132,13 @@ device cannot transmit.
.SH IOCTL COMMANDS
.PP
The LIRC device's ioctl definition is bound by the ioctl function
definition of struct file_operations, leaving us with an unsigned
int for the ioctl command and an unsigned long for the argument.
definition of
.IR "struct file_operations" ,
leaving us with an
.IR "unsigned int"
for the ioctl command and an
.IR "unsigned long"
for the argument.
For the purposes of ioctl portability across 32-bit and 64-bit architectures,
these values are capped to their 32-bit sizes.
.PP
@ -171,8 +176,9 @@ devices support the 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 will return ENOTTY.
If a driver does not announce support of certain features, invoking
the corresponding ioctls will fail with the error
.BR ENOTTY .
.TP
.BR LIRC_GET_REC_MODE " (\fIvoid\fP)"
If the
@ -180,7 +186,7 @@ If the
device has no receiver return
.B ENOTTY,
else return the receive mode, which will be one of:
.RS 4
.RS
.TP
.BR LIRC_MODE_MODE2
The driver returns a sequence of pulse/space durations.
@ -244,7 +250,7 @@ are reserved for future use.
.BR LIRC_GET_MIN_TIMEOUT " (\fIvoid\fP)", " "\
LIRC_GET_MAX_TIMEOUT " (\fIvoid\fP)"
Some devices have internal timers that can be used to detect when
there's no IR activity for a long time.
there has been no IR activity for a long time.
This can help
.BR lircd (8)
in detecting that an IR signal is finished and can speed up the
@ -274,7 +280,7 @@ than the given value should be set.
.TP
.BR LIRC_GET_REC_TIMEOUT " (\fivoid\fP)"
Return the current inactivity timeout (microseconds).
Available in kernel release 4.18 and later.
Available since Linux 4.18.
.TP
.BR LIRC_SET_REC_TIMEOUT_REPORTS " (\fIint\fP)"
Enable
@ -321,7 +327,7 @@ is 0) the measure mode.
If enabled, from the next key press on, the driver will send
.BR LIRC_MODE2_FREQUENCY
packets.
By default this should be turned off.
By default, this should be turned off.
.TP
.BR LIRC_GET_REC_RESOLUTION " (\fIvoid\fP)"
Return the driver resolution (microseconds).
@ -347,7 +353,7 @@ equals 0) this functionality.
This might be useful for devices that otherwise have narrow band
receivers that prevent them to be used with certain remotes.
Wide band receivers may also be more precise.
On the other hand its disadvantage usually is reduced range of
On the other hand, their disadvantage usually is reduced range of
reception.
.IP
Note: wide band receiver may be implicitly enabled if you enable
@ -358,8 +364,7 @@ will do nothing.
.\"
.SH FEATURES
.PP
The features returned by
The
the
.BR LIRC_GET_FEATURES
ioctl returns a bit mask describing features of the driver.
The following bits may be returned in the mask: