1 .. SPDX-License-Identifier: GPL-2.0
2
3 ==============================================
4 Infrared remote control support in video4linux
5 ==============================================
6
7 Authors: Gerd Hoffmann, Mauro Carvalho Chehab
8
9 Basics
10 ======
11
12 Most analog and digital TV boards support remo
13 them have a microprocessor that receives the I
14 pulse/space sequences and then to scan codes,
15 userspace ("scancode mode"). Other boards retu
16 sequences ("raw mode").
17
18 The support for remote controller in scancode
19 standard Linux input layer. The support for ra
20
21 In order to check the support and test it, it
22 the `v4l-utils <https://git.linuxtv.org/v4l-ut
23 two tools to handle remote controllers:
24
25 - ir-keytable: provides a way to query the rem
26 protocols it supports, enable in-kernel supp
27 switch the protocol and to test the receptio
28
29 - ir-ctl: provide tools to handle remote contr
30 via LIRC interface.
31
32 Usually, the remote controller module is auto-
33 detected. However, for a few devices, you need
34 ir-kbd-i2c module.
35
36 How it works
37 ============
38
39 The modules register the remote as keyboard wi
40 layer, i.e. you'll see the keys of the remote
41 (if CONFIG_INPUT_KEYBOARD is enabled).
42
43 Using the event devices (CONFIG_INPUT_EVDEV) i
44 applications to access the remote via /dev/inp
45 The udev/systemd will automatically create the
46 the `v4l-utils <https://git.linuxtv.org/v4l-ut
47 automatically load a different keytable than t
48 `v4l-utils <https://git.linuxtv.org/v4l-utils.
49 man page for details.
50
51 The ir-keytable tool is nice for trouble shoot
52 whenever the input device is really present, w
53 is, check whenever pressing keys on the remote
54 events and the like. You can also use any oth
55 the keymaps, like the input kbd utility.
56
57
58 Using with lircd
59 ----------------
60
61 The latest versions of the lircd daemon suppor
62 linux input layer (via event device). It also
63 in lirc mode.
64
65
66 Using without lircd
67 -------------------
68
69 Xorg recognizes several IR keycodes that have
70 than 247. With the advent of Wayland, the inpu
71 and should now accept all keycodes. Yet, you m
72 the keycodes to something that your favorite m
73
74 This can be done by setting
75 `v4l-utils <https://git.linuxtv.org/v4l-utils.
76 keytable in runtime. Please read ir-keytable.
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