Arch Teapot Notes 12-02-18

Multimedia Keys

We learned that multimedia keys are available by using xev. To use it, start xev | grep keycode and press the buttons in question.

Notice: if your window manager evaluates the pressed keycodes, nothing will show up.

The shown keycodes should be placed in ~/.Xmodmap and loaded on X startup by xmodmap ~/.Xmodmap.

Example (ThinkPad X61):

keycode 113 = XF86AudioMute
keycode 114 = XF86AudioLowerVolume
keycode 115 = XF86AudioRaiseVolume
keycode 148 = XF86Launch1 # ThinkVantage Button
keycode 163 = XF86AudioNext
keycode 164 = XF86AudioPlay
keycode 165 = XF86AudioPrev
keycode 166 = XF86AudioStop

The terminal based program showkeys won’t work, since kernel keycodes differ from X11.

ArchWiki Xmodmap

These keysyms can be used for your favorite window manager‘s configuration.

Example (awesome):

  -- Multimedia Keys
    awful.key({ }, "XF86AudioRaiseVolume", function () awful.util.spawn('mpc -h localhost volume +1') end),
    awful.key({ }, "XF86AudioLowerVolume", function () awful.util.spawn('mpc -h localhost volume -1') end),
    awful.key({ }, "XF86AudioMute", function () awful.util.spawn('mpc -h localhost volume 0') end),
    awful.key({ }, "XF86AudioNext", function () awful.util.spawn('mpc -h localhost next') end),
    awful.key({ }, "XF86AudioPrev", function () awful.util.spawn('mpc -h localhost prev') end),
    awful.key({ }, "XF86AudioPlay", function () awful.util.spawn('mpc -h localhost toggle') end)

PulseAudio

PulseAudio is a sound system enabling us to control application volumes individually and use other computers soundcards over the network.

Recommended packages:

• pulseaudio (the daemon, required)
• pavucontrol (GTK based mixer application)
• paprefs (GTK based configuration tool)
• pulseaudio-alsa

With pulseaudio-alsa, applications may use a virtual ALSA device for output. They show up as regular PulseAudio clients and there is an ALSA mixer channel to control the volume.

Note: in order to discover remote soundcards, one has to start avahi-daemon!