Ubuntu – How to disable multimedia keys entirely? 18.04 LTS

gnomekeyboardmedia-buttonsxkbxmodmap

I have a fresh vanilla 18.04 LTS install, using gnome-shell 3.28.4. I'm using a wired Apple aluminum keyboard:

I would like to use the top-row F-keys as keyboard shortcuts in various end-user applications (Firefox, CLion, etc), but whenever I press any of them, something in the gnome/X11 stack (I assume) is intercepting them and interpreting them as "media" keys. Such F-row keypresses are not delivered to any application, as far as I can tell.

For example, if I press F5, I'd like Firefox to reload the current webpage, or CLion to trigger a build, but instead, the only thing that happens is that the following giant icon is overlaid on the screen:

I've played around with gnome-tweaks and the settings app, to no avail. I've also looked around in dconf-editor, but I'm not familiar with it and haven't changed anything in there because I don't know what I'm doing.

I've done a lot of searching, but the only hits I've gotten seem to be from people whose media aren't working (and they want them to be working). To be clear, I want to disable media keys entirely.

Does anyone know how to do this? Thanks!

Update 1: output of cat /usr/share/X11/xkb/symbols/pc:

daniel@legolas:~$  cat /usr/share/X11/xkb/symbols/pc
default  partial alphanumeric_keys modifier_keys
xkb_symbols "pc105" {

    key <ESC>  {    [ Escape        ]   };

    // The extra key on many European keyboards:
    key <LSGT> {    [ less, greater, bar, brokenbar ] };

    // The following keys are common to all layouts.
    key <BKSL> {    [ backslash,    bar ]   };
    key <SPCE> {    [    space      ]   };

    include "srvr_ctrl(fkey2vt)"
    include "pc(editing)"
    include "keypad(x11)"

    key <BKSP> {    [ BackSpace, BackSpace  ]   };

    key  <TAB> {    [ Tab,  ISO_Left_Tab    ]   };
    key <RTRN> {    [ Return        ]   };

    key <CAPS> {    [ Caps_Lock     ]   };
    key <NMLK> {    [ Num_Lock      ]   };

    key <LFSH> {    [ Shift_L       ]   };
    key <LCTL> {    [ Control_L     ]   };
    key <LWIN> {    [ Super_L       ]   };

    key <RTSH> {    [ Shift_R       ]   };
    key <RCTL> {    [ Control_R     ]   };
    key <RWIN> {    [ Super_R       ]   };
    key <MENU> {    [ Menu          ]   };

    // Beginning of modifier mappings.
    modifier_map Shift  { Shift_L, Shift_R };
    modifier_map Lock   { Caps_Lock };
    modifier_map Control{ Control_L, Control_R };
    modifier_map Mod2   { Num_Lock };
    modifier_map Mod4   { Super_L, Super_R };

    // Fake keys for virtual<->real modifiers mapping:
    key <LVL3> {    [ ISO_Level3_Shift  ]   };
    key <MDSW> {    [ Mode_switch       ]   };
    modifier_map Mod5   { <LVL3>, <MDSW> };

    key <ALT>  {    [ NoSymbol, Alt_L   ]   };
    include "altwin(meta_alt)"

    key <META> {    [ NoSymbol, Meta_L  ]   };
    modifier_map Mod1   { <META> };

    key <SUPR> {    [ NoSymbol, Super_L ]   };
    modifier_map Mod4   { <SUPR> };

    key <HYPR> {    [ NoSymbol, Hyper_L ]   };
    modifier_map Mod4   { <HYPR> };
    // End of modifier mappings.

    key <OUTP> { [ XF86Display ] };
    key <KITG> { [ XF86KbdLightOnOff ] };
    key <KIDN> { [ XF86KbdBrightnessDown ] };
    key <KIUP> { [ XF86KbdBrightnessUp ] };
};

hidden partial alphanumeric_keys
xkb_symbols "editing" {
    key <PRSC> {
    type= "PC_ALT_LEVEL2",
    symbols[Group1]= [ Print, Sys_Req ]
    };
    key <SCLK> {    [  Scroll_Lock      ]   };
    key <PAUS> {
    type= "PC_CONTROL_LEVEL2",
    symbols[Group1]= [ Pause, Break ]
    };
    key  <INS> {    [  Insert       ]   };
    key <HOME> {    [  Home         ]   };
    key <PGUP> {    [  Prior        ]   };
    key <DELE> {    [  Delete       ]   };
    key  <END> {    [  End          ]   };
    key <PGDN> {    [  Next         ]   };

    key   <UP> {    [  Up           ]   };
    key <LEFT> {    [  Left         ]   };
    key <DOWN> {    [  Down         ]   };
    key <RGHT> {    [  Right        ]   };
};

Best Answer

Are keyboard multimedia keys different?

Yes, these keys are a little different. They might report a single key code or multiple key codes when pressed with other keys like Fn for example. Furthermore, it is oftentimes difficult to identify their key codes with utilities like xev. This depends on the keyboard's manufacture's configuration.

Multimedia keys, usually, have their key codes configured with XF86 key names. These names differ but start with XF86 like XF86MonBrightnessUp and XF86MonBrightnessDown and so on.

How to disable/reconfigure keyboard multimedia keys?

`XKB` Method

The easiest method is to edit the XKB configuration file like so:

Edit the XKB /usr/share/X11/xkb/symbols/pc file by running the following command in the terminal:

sudo nano /usr/share/X11/xkb/symbols/pc
Find lines that contain XF86 like so:

key <KEY_CODE> { [ XF86MonBrightnessDown ] };
Comment them out by adding // before them like so:

//key <KEY_CODE> { [ XF86MonBrightnessDown ] };
Save the file and exit the editor by pressing Ctrl + X then press Y.
Clear the XKB cache by running the following command in the terminal:

sudo rm -rf /var/lib/xkb/*
Reboot your system to activate your new XKB configuration or alternatively you can avoid reboot and try to reload the new XKB configuration by setting an XKB map layout using the following command in the terminal:

setxkbmap -layout us
Test your keys.

If the keyboard multimedia keys are configured by the manufacturer to report a single key code, the above solution might disable them and leave the keys free to be used for other purposes.

If, however, this is not the case, then you will need to deal with xmodmap.

`xmodmap` Method

The xmodmap method is a little different and you cannot just disable multimedia keys using this method and assign them to nothing like so xmodmap -e 'keycode Number =' because this, oftentimes, will render them unusable so you will need to reassign them to the desired functions. You will also need to put in action some mechanism to maintain your changes between reboots and logouts/logins.

To implement this method, please follow the steps below:

Show the current keyboard map by running the following command in the terminal:

xmodmap -pke
Inspect the output and identify lines that contain XF68 right after the = sign like so:

keycode 232 = XF86MonBrightnessDown NoSymbol XF86MonBrightnessDown NoSymbol XF86MonBrightnessDown

The above line, for example, shows that the key with code number 232 is currently configured to trigger XF86MonBrightnessDown which will decrease the monitor's brightness and you can change this behavior by assigning a different value to it like so xmodmap -e 'keycode 232 = New_Value'. For example to assign the F11 functionality to this multimedia key, please run the following command in the terminal:

xmodmap -e 'keycode 232 = F11'

The new functionality will be effective immediately. This change in functionality will, however, be lost after reboot or logout/login.

Notice: It might be helpful to run the acpi_listen command in the terminal and monitor the output as you press the actual physical key then compare it to the output you got from xmodmap -pke so that you confirm the key code is for the one you want. You can also try the xev utility but, unfortunately it will not always return a key code when dealing with multimedia or vendor specific keys.

To preserve the change after reboots and logouts/logins, you will need to do the following:

Create and edit a script file in your home directory by running the following command in the terminal:

nano ~/.Modify_Multimedia_Keys.sh
Add this #!/bin/bash in the first line then add your xmodmap -e 'keycode Number = New_Value' commands below the first line ( each command in a single new line ) like so:

#!/bin/bash
xmodmap -e 'keycode 232 = F11'
xmodmap -e 'keycode 122 = F2'

Save the script file and exit the editor by pressing Ctrl + X then press Y.
Make the script file executable by running the following command in the terminal:

chmod +x ~/.Modify_Multimedia_Keys.sh
Make the script file execute at each start-up either by adding it to your Startup Applications through the GUI or by placing a Modify_Multimedia_Keys.desktop file in the ~/.config/autostart/ directory that contains the following content replacing YOUR_USERNAME with your actual username:

[Desktop Entry]
Type=Application
Exec=/home/YOUR_USERNAME/.Modify_Multimedia_Keys.sh
Hidden=false
X-GNOME-Autostart-enabled=true
Name=Modify Multimedia Keys
Comment=This modifies keyboard multimedia keys

xmodmap

Moving up and down via CAPS and Shift+CAPS works on my system with the given .Xmodmap as expected.

You check whether your settings are actually in affect by calling

$ xmodmap -pk | grep ^\\s*66
     66     0xffe5 (Caps_Lock)  0x0000 (NoSymbol)   0xffe5 (Caps_Lock)
$ setxkbmap -layout us && xmodmap ~/.Xmodmap
$ xmodmap -pk | grep ^\\s*66
     66     0xff54 (Down)   0xff52 (Up)

the LEVEL2 Modifier

There is another (real) problem to your question that comes next:

The LEVEL2 <SHIFT> modifier which is activated by pressing the Shift button is there to visually mark characters in a text editor when moving through the lines with the arrow keys. If you assign <UP> ↑ to the second level of <CAPS>, what you are effectively doing is pressing Shift+↑. You have to deactivate the Shift modifier just for that scenario. Afaik you can not do this using xmodmap.

redirecting LEVEL2 Modifier

The "real way" of modifying key maps is with xkb. I found the solution on an old xorg mailing list. The LEVEL2 of Caps has to get redirected to the ↑(<UP>) key (The Up-Key btw has only one level.) On X.org you can deactivating the Shift modifier during redirect with the built-in function RedirectKey(key=<UP>, clearmods=Shift). clearmods "releases" the Shift modifier before the the key is actually "pressed".

layout file

The simplest way to activate the behavior is to create a new layout file:

/usr/share/X11/xkb/symbols/capslockarrow

default partial xkb_symbols "basic" {

    include "de(basic)"
    include "shift(both_capslock_cancel)"

    key <CAPS> {
        type[Group1] = "TWO_LEVEL",
        symbols[Group1] = [ Down, NoSymbol ],
        actions[Group1] = [ NoAction(), RedirectKey(key=<UP>, clearmods=Shift) ]
    };
 };

activate the new layout with

setxkbmap capslockarrow

Notes on the layout file

The new layout file derives from de(basic). That is the layout for the standard german keyboard. You can add any other layout here like us(basic) or us(euro). see /usr/share/X11/xkb/symbols/ to get a glance of what is possible. The two letter code is the filename and in brackets is the respective xkb_symbols definition from the file.
You would not have a caps key modifier anymore. Therefore I added a sort of replacement for Caps: shift(both_capslock_cancel) By pressing both LSHIFT and RSHIFT together, you can activate CAPS Lock and you release the Lock again with any other press of a Shift key.
If anyone is wondering why I did not use a new type definition for that: I simply could not release the Shift modifier before the action of the Up Key was triggered. Releasing the Shift key though should be possible by explicitly calling preserve[Shift] = None in a spearated xkb_types.
As stated in the comments below, Wayland will also rely on XKB but will not allow redirections.

Ubuntu – While Shift+1 prints the exclamation mark, the key “1” does not work!

Narrow it down to hardware or software

First check to see if it is OS software, Application Tools or Laptop BIOS which is causing interference:

Boot with Live USB and select "Try Ubuntu without Installing". Does the 1 key work properly? If not try step 2. If yes reinstall Ubuntu 18.10.
Boot your laptop but interrupt Grub by pressing c key for command. Does the 1 key work properly? If Yes it is a problem with Ubuntu 18.10. If not go to step 3.
Get a USB keyboard (they start at $10 if you can't borrow one) and plug it in. Boot your laptop normally. Does the 1 key work properly? If not try step 4. If yes check Dell Update website and install this:
Try using Windows 7/8/10. Does problem still exist?

Best Answer

XKB Method

xmodmap Method

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