Enable support for mute media key

media_control.lua

@@ -28,11 +28,18 @@ end
 
 -- Volume control
 function getVolume()
+    if isMuted() then return 0 end
     local handle = io.popen("amixer -D pulse sget Master | awk -F\"[][]\" '/%/ { print $2 }' | head -n 1", "r")
     local volume = string.gsub(handle:read("*a"), "[\n%%]+", "") / 100
     handle:close()
     return volume
 end
+function isMuted()
+    local handle = io.popen("amixer -D pulse sget Master | awk -F\"[][]\" '/[onf]{2,3}/ { print $4 }' | head -n -1", "r")
+    local muted = string.gsub(handle:read("*a"), "[\n]+", "") == "off"
+    handle:close()
+    return muted
+end
 
 function getVolumeImage(volume)
     local path = beautiful.volume_osd_icon_3
@@ -161,6 +168,11 @@ local lowerVolume = function()
     os.execute("amixer -D pulse set Master 5%-")
     displayVolume()
 end
+local toggleMute = function()
+    local muted = isMuted()
+    os.execute("amixer -D pulse set Master " .. (muted and 'on' or 'off'))
+    displayVolume()
+end
 -- }}}
 
 return {
@@ -168,5 +180,6 @@ return {
     nextTrack = nextTrack,
     previousTrack = previousTrack,
     raiseVolume = raiseVolume,
-    lowerVolume = lowerVolume
+    lowerVolume = lowerVolume,
+    toggleMute = toggleMute
 }

rc.lua

@@ -441,7 +441,9 @@ globalkeys = gears.table.join(
     awful.key({}, "XF86AudioRaiseVolume", media_control.raiseVolume,
         {description = "Raise volume", group="media control"}),
     awful.key({}, "XF86AudioLowerVolume", media_control.lowerVolume,
-        {description = "Lower volume", group="media control"})
+        {description = "Lower volume", group="media control"}),
+    awful.key({}, "XF86AudioMute", media_control.toggleMute,
+        {description = "Toggle mute audio", group="media control"})
 )
 
 clientkeys = gears.table.join(