MythTV: Use All Buttons of Your Remote Control - Without LIRC

It can be really frustrating to get a remote control to work properly under Linux with LIRC and programs like MythTV, mplayer or XMBC. This article shows how to avoid using LIRC altogether: Treat the remote like any other keyboard, then change the keyboard mapping to use the application's key shortcuts. Because we do this before the keypresses reach X11, it avoids the dreaded problem of keys with codes >255 not working.


The Problem

LIRC is used by many programs to receive input from a remote control. When LIRC was first written, it was great to have a shared API so you could use any remote with any program. However, it was also always a hassle to configure remotes to work properly. These days, new programs should use the Linux kernel's nice unified "evdev" interface together with the IR keymaps that have also become part of the kernel, but unfortunately many programs still depend on the LIRC user-space setup with its unrecognized (or double-pressed) buttons and extra delay after button presses.

Recently, I tried (not for the first time) to get one of my two remotes working with MythTV and got annoyed at LIRC again: Only some buttons on the remote worked, others such as the all-important "OK" button were not recognized in MythTV.

Searching about the problem on the web turns up no end of complicated/expensive advice: The MythTV Wiki suggests bypassing LIRC by buying both an IR keyboard and a universal remote that can be reprogrammed to send the keyboard codes. Alternatively, you can buy the flirc device, or you can patch and recompile your X11 evdev driver. Furthermore, you always need to find a matching lircd.conf for your remote and test the setup with irw or mode2 before even trying out MythTV.

A better solution is simply to remap the keycodes of the remote on the kernel side, before they reach X11. Apparently the first mention of this approach is this post on the XMBC forum by "darkscout", also Wyliecoyoteuk described it in his post How to forget LIRC for MythTV remotes. Below, I'm providing some copy & paste shell code snippets to make the process simpler.

Requirements

  • A remote control that provides an "evdev" (dev/input) interface. Most recent remotes that are supported under Linux have this.
  • The ir-keytable tool.
  • Optionally, the irrecord program from the LIRC distribution to output a list of all possible keycode names.

Note: All of the following commands need access to the remote's device. To avoid any related problems, best work as root.

Step 0: Does the Kernel Know About the Remote?

Execute ir-keytable -t, then press a few buttons on the remote. If nothing is output, you need to check whether the remote is supported and the respective kernel module is loaded.

Step 1: Find Device for Your Remote Control

Simply execute ir-keytable without any arguments. This is the example output for my X10 MCE remote (a 2.4 GHz radio remote, not IR). We are interested in the device path under /dev:

# ir-keytable
Found /sys/class/rc/rc0/ (/dev/input/event7) with:
	Driver ati_remote, table rc-medion-x10-or2x
	Supported protocols: other 
	Enabled protocols: 
	Repeat delay = 500 ms, repeat period = 125 ms

My other remote (an old Terratec Cinergy T²) does not appear here, but it can be found by looking at the right directory inside /dev:

# ls -l /dev/input/by-path/*-ir
lrwxrwxrwx 1 root root 9 May 20 14:22 
/dev/input/by-path/pci-0000:00:1a.7-usb-0:4-event-ir -> ../event6

Step 2: Record Default Keyboard Map

Execute ir-keytable --read --device=/dev/input/PATH to get the current kernel-provided mapping for the remote (excerpt):

scancode 0x001e = KEY_OK (0x160)
scancode 0x0020 = KEY_BACK (0x9e)
scancode 0x002f = KEY_INFO (0x166)
scancode 0x0031 = KEY_EPG (0x16d)

Step 3: Edit Keyboard Map

Note the highlighted keycodes above which have 3 digits after the "0x", i.e. the values are >255. We want to remap them to values <=255 to avoid all the problems with unrecognized button presses. But I suggest to also remap the other buttons for convenience: For example, in MythTV Play/Pause is the keyboard shortcut "P", so you can remap that button on the remote to the "P" key and leave the MythTV setup unchanged.

A list of available keycodes is output by irrecord -l, or see below.

It is up to you what keys to assign to the buttons. For a setup with a single application, the easiest approach is to use the application's shortcuts directly. In other cases, you may want to use rarely-used keys (e.g. KEY_F13 keys and higher or the numeric keypad, KEY_KP0) and assign shortcuts in the application. You can only configure simple key presses and not Shift/Ctrl combinations - if you need the latter, first cause a simple keypress to execute a custom command (e.g. with Gnome's keyboard shortcuts) and then use a utility like xdotool to synthesize a key combination in X11.

For the example above, I mapped the keys to the MythTV shortcuts:

scancode 0x001e = KEY_ENTER # was KEY_OK
scancode 0x0020 = KEY_ESC # was KEY_BACK
scancode 0x002f = KEY_I # was KEY_INFO
scancode 0x0031 = KEY_S # was KEY_EPG

Step 4: Load New Keyboard Map - Profit!

To make the remote use the changed keymap, execute:
ir-keytable --write=FILENAME --device=/dev/input/PATH

To make the setting permanent, you can execute the command from udev once the device is detected. Alternatively, just put it into a startup script, but then remember to explicitly load the relevant kernel module for your hardware before executing it. Under Debian, put your file into /etc/rc_keymaps and add information about the driver, table and file in /etc/rc_maps.cfg


Keycodes

KEY_0
KEY_102ND
KEY_1
KEY_2
KEY_3
KEY_4
KEY_5
KEY_6
KEY_7
KEY_8
KEY_9
KEY_A
KEY_AB
KEY_ADDRESSBOOK
KEY_AGAIN
KEY_ALTERASE
KEY_ANGLE
KEY_APOSTROPHE
KEY_ARCHIVE
KEY_AUDIO
KEY_AUX
KEY_B
KEY_BACK
KEY_BACKSLASH
KEY_BACKSPACE
KEY_BASSBOOST
KEY_BATTERY
KEY_BLUE
KEY_BLUETOOTH
KEY_BOOKMARKS
KEY_BREAK
KEY_BRIGHTNESS_CYCLE
KEY_BRIGHTNESSDOWN
KEY_BRIGHTNESSUP
KEY_BRIGHTNESS_ZERO
KEY_BRL_DOT10
KEY_BRL_DOT1
KEY_BRL_DOT2
KEY_BRL_DOT3
KEY_BRL_DOT4
KEY_BRL_DOT5
KEY_BRL_DOT6
KEY_BRL_DOT7
KEY_BRL_DOT8
KEY_BRL_DOT9
KEY_C
KEY_CALC
KEY_CALENDAR
KEY_CAMERA
KEY_CANCEL
KEY_CAPSLOCK
KEY_CD
KEY_CHANNEL
KEY_CHANNELDOWN
KEY_CHANNELUP
KEY_CHAT
KEY_CLEAR
KEY_CLOSE
KEY_CLOSECD
KEY_COFFEE
KEY_COMMA
KEY_COMPOSE
KEY_COMPUTER
KEY_CONFIG
KEY_CONNECT
KEY_CONTEXT_MENU
KEY_COPY
KEY_CUT
KEY_CYCLEWINDOWS
KEY_D
KEY_DASHBOARD
KEY_DATABASE
KEY_DEL_EOL
KEY_DEL_EOS
KEY_DELETE
KEY_DELETEFILE
KEY_DEL_LINE
KEY_DIGITS
KEY_DIRECTION
KEY_DIRECTORY
KEY_DISPLAY_OFF
KEY_DISPLAYTOGGLE
KEY_DOCUMENTS
KEY_DOLLAR
KEY_DOT
KEY_DOWN
KEY_DVD
KEY_E
KEY_EDIT
KEY_EDITOR
KEY_EJECTCD
KEY_EJECTCLOSECD
KEY_EMAIL
KEY_END
KEY_ENTER
KEY_EPG
KEY_EQUAL
KEY_ESC
KEY_EURO
KEY_EXIT
KEY_F10
KEY_F11
KEY_F12
KEY_F13
KEY_F14
KEY_F15
KEY_F1
KEY_F16
KEY_F17
KEY_F18
KEY_F19
KEY_F20
KEY_F21
KEY_F22
KEY_F23
KEY_F24
KEY_F2
KEY_F
KEY_F3
KEY_F4
KEY_F5
KEY_F6
KEY_F7
KEY_F8
KEY_F9
KEY_FASTFORWARD
KEY_FAVORITES
KEY_FILE
KEY_FINANCE
KEY_FIND
KEY_FIRST
KEY_FN
KEY_FN_1
KEY_FN_2
KEY_FN_B
KEY_FN_D
KEY_FN_E
KEY_FN_ESC
KEY_FN_F
KEY_FN_F10
KEY_FN_F1
KEY_FN_F11
KEY_FN_F12
KEY_FN_F2
KEY_FN_F3
KEY_FN_F4
KEY_FN_F5
KEY_FN_F6
KEY_FN_F7
KEY_FN_F8
KEY_FN_F9
KEY_FN_S
KEY_FORWARD
KEY_FORWARDMAIL
KEY_FRAMEBACK
KEY_FRAMEFORWARD
KEY_FRONT
KEY_G
KEY_GAMES
KEY_GOTO
KEY_GRAPHICSEDITOR
KEY_GRAVE
KEY_GREEN
KEY_H
KEY_HANGEUL
KEY_HANJA
KEY_HELP
KEY_HENKAN
KEY_HIRAGANA
KEY_HOME
KEY_HOMEPAGE
KEY_HP
KEY_I
KEY_INFO
KEY_INSERT
KEY_INS_LINE
KEY_ISO
KEY_J
KEY_K
KEY_KATAKANA
KEY_KATAKANAHIRAGANA
KEY_KBDILLUMDOWN
KEY_KBDILLUMTOGGLE
KEY_KBDILLUMUP
KEY_KEYBOARD
KEY_KP0
KEY_KP1
KEY_KP2
KEY_KP3
KEY_KP4
KEY_KP5
KEY_KP6
KEY_KP7
KEY_KP8
KEY_KP9
KEY_KPASTERISK
KEY_KPCOMMA
KEY_KPDOT
KEY_KPENTER
KEY_KPEQUAL
KEY_KPJPCOMMA
KEY_KPLEFTPAREN
KEY_KPMINUS
KEY_KPPLUS
KEY_KPPLUSMINUS
KEY_KPRIGHTPAREN
KEY_KPSLASH
KEY_L
KEY_LANGUAGE
KEY_LAST
KEY_LEFT
KEY_LEFTALT
KEY_LEFTBRACE
KEY_LEFTCTRL
KEY_LEFTMETA
KEY_LEFTSHIFT
KEY_LINEFEED
KEY_LIST
KEY_LOGOFF
KEY_M
KEY_MACRO
KEY_MAIL
KEY_MAX
KEY_MEDIA
KEY_MEDIA_REPEAT
KEY_MEMO
KEY_MENU
KEY_MESSENGER
KEY_MHP
KEY_MINUS
KEY_MODE
KEY_MOVE
KEY_MP3
KEY_MSDOS
KEY_MUHENKAN
KEY_MUTE
KEY_N
KEY_NEW
KEY_NEWS
KEY_NEXT
KEY_NEXTSONG
KEY_NUMERIC_0
KEY_NUMERIC_1
KEY_NUMERIC_2
KEY_NUMERIC_3
KEY_NUMERIC_4
KEY_NUMERIC_5
KEY_NUMERIC_6
KEY_NUMERIC_7
KEY_NUMERIC_8
KEY_NUMERIC_9
KEY_NUMERIC_POUND
KEY_NUMERIC_STAR
KEY_NUMLOCK
KEY_O
KEY_OK
KEY_OPEN
KEY_OPTION
KEY_P
KEY_PAGEDOWN
KEY_PAGEUP
KEY_PASTE
KEY_PAUSE
KEY_PAUSECD
KEY_PC
KEY_PHONE
KEY_PLAY
KEY_PLAYCD
KEY_PLAYER
KEY_PLAYPAUSE
KEY_POWER
KEY_POWER2
KEY_PRESENTATION
KEY_PREVIOUS
KEY_PREVIOUSSONG
KEY_PRINT
KEY_PROG1
KEY_PROG2
KEY_PROG3
KEY_PROG4
KEY_PROGRAM
KEY_PROPS
KEY_PVR
KEY_Q
KEY_QUESTION
KEY_R
KEY_RADIO
KEY_RECORD
KEY_RED
KEY_REDO
KEY_REFRESH
KEY_REPLY
KEY_RESERVED
KEY_RESTART
KEY_REWIND
KEY_RFKILL
KEY_RIGHT
KEY_RIGHTALT
KEY_RIGHTBRACE
KEY_RIGHTCTRL
KEY_RIGHTMETA
KEY_RIGHTSHIFT
KEY_RO
KEY_S
KEY_SAT
KEY_SAT2
KEY_SAVE
KEY_SCALE
KEY_SCREEN
KEY_SCROLLDOWN
KEY_SCROLLLOCK
KEY_SCROLLUP
KEY_SEARCH
KEY_SELECT
KEY_SEMICOLON
KEY_SEND
KEY_SENDFILE
KEY_SETUP
KEY_SHOP
KEY_SHUFFLE
KEY_SLASH
KEY_SLEEP
KEY_SLOW
KEY_SOUND
KEY_SPACE
KEY_SPELLCHECK
KEY_SPORT
KEY_SPREADSHEET
KEY_STOP
KEY_STOPCD
KEY_SUBTITLE
KEY_SUSPEND
KEY_SWITCHVIDEOMODE
KEY_SYSRQ
KEY_T
KEY_TAB
KEY_TAPE
KEY_TEEN
KEY_TEXT
KEY_TIME
KEY_TITLE
KEY_TUNER
KEY_TV
KEY_TV2
KEY_TWEN
KEY_U
KEY_UNDO
KEY_UNKNOWN
KEY_UP
KEY_UWB
KEY_V
KEY_VCR
KEY_VCR2
KEY_VENDOR
KEY_VIDEO
KEY_VIDEO_NEXT
KEY_VIDEOPHONE
KEY_VIDEO_PREV
KEY_VOICEMAIL
KEY_VOLUMEDOWN
KEY_VOLUMEUP
KEY_W
KEY_WAKEUP
KEY_WIMAX
KEY_WLAN
KEY_WORDPROCESSOR
KEY_WWW
KEY_X
KEY_XFER
KEY_Y
KEY_YELLOW
KEY_YEN
KEY_Z
KEY_ZENKAKUHANKAKU
KEY_ZOOM
KEY_ZOOMIN
KEY_ZOOMOUT
KEY_ZOOMRESET
BTN_0
BTN_1
BTN_2
BTN_3
BTN_4
BTN_5
BTN_6
BTN_7
BTN_8
BTN_9
BTN_A
BTN_B
BTN_BACK
BTN_BASE
BTN_BASE2
BTN_BASE3
BTN_BASE4
BTN_BASE5
BTN_BASE6
BTN_C
BTN_DEAD
BTN_DIGI
BTN_EXTRA
BTN_FORWARD
BTN_GAMEPAD
BTN_GEAR_DOWN
BTN_GEAR_UP
BTN_JOYSTICK
BTN_LEFT
BTN_MIDDLE
BTN_MISC
BTN_MODE
BTN_MOUSE
BTN_PINKIE
BTN_RIGHT
BTN_SELECT
BTN_SIDE
BTN_START
BTN_STYLUS
BTN_STYLUS2
BTN_TASK
BTN_THUMB
BTN_THUMB2
BTN_THUMBL
BTN_THUMBR
BTN_TL
BTN_TL2
BTN_TOOL_AIRBRUSH
BTN_TOOL_BRUSH
BTN_TOOL_DOUBLETAP
BTN_TOOL_FINGER
BTN_TOOL_LENS
BTN_TOOL_MOUSE
BTN_TOOL_PEN
BTN_TOOL_PENCIL
BTN_TOOL_QUADTAP
BTN_TOOL_RUBBER
BTN_TOOL_TRIPLETAP
BTN_TOP
BTN_TOP2
BTN_TOUCH
BTN_TR
BTN_TR2
BTN_TRIGGER
BTN_WHEEL
BTN_X
BTN_Y
BTN_Z

Thanks

Thanks for sharing this.

I get "/sys/class/rc/: No

I get "/sys/class/rc/: No such file or directory" when trying to run "ir-keytable -t" but the remote does work, i was actually using it in the terminal to issue the command (arrow keys, enter, etc)

Dont know if you have any ideas about that? - i am using Rpi3, raspbian

Try "sudo ir-keymap" alone to

Try "sudo ir-keymap" alone to see which device (/dev/input/eventX) you need to use with the -d option.

Special Keys

Is there a KEY_CODE for the Windows/Super/Start key?

Most keyboards have the Windows symbol, but some have Mr Tux, and I really need to map an IR keypress to activate this button.

Thanks

KEY_COMPOSE

I think KEY_COMPOSE might do the trick.

Thanks for the great guide -

Thanks for the great guide - it was exactly what I needed.

I have NEVER had an issue

I have NEVER had an issue with LIRC. LIRC is able to handle any remote I have EVER tried.

ir-keytable on the other hand has only worked a few times.

Here is a great tutorial someone made on XBMC forums. Any IR remote and any button.

http://forum.xbmc.org/showthread.php?tid=170372