How are the XF86Audio* function keys mapped? Confused.

coralfang · 08-18-2019, 12:10 AM

A problem i've been having for years on various distributions, is that all of my function keys related to audio never work as you'd expect.

When loading up a "barebones" desktop, something such as Fluxbox, AwesomeWM etc, these keys will fail to do anything;

* XF86AudioMute
* XF86AudioRaiseVolume
* XF86AudioLowerVolume

The tool `xev` will not display any keysym/keycode values at all, so i cannot map them correctly using `xmodmap`.

However, when launching something such as `kmix` in the background, the keys are suddenly recognized, also showing useful information within `xev`...

* XF86AudioMute

Code:

KeyRelease event, serial 38, synthetic NO, window 0x3600001,
    root 0x1ce, subw 0x0, time 869236, (956,323), root:(958,341),
    state 0x0, keycode 121 (keysym 0x1008ff12, XF86AudioMute), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

* XF86AudioRaiseVolume

Code:

KeyRelease event, serial 36, synthetic NO, window 0x3600001,
    root 0x1ce, subw 0x0, time 926386, (638,441), root:(640,459),
    state 0x0, keycode 123 (keysym 0x1008ff13, XF86AudioRaiseVolume), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

* XF86AudioLowerVolume

Code:

KeyRelease event, serial 36, synthetic NO, window 0x3600001,
    root 0x1ce, subw 0x0, time 929258, (638,441), root:(640,459),
    state 0x0, keycode 122 (keysym 0x1008ff11, XF86AudioLowerVolume), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

Given that useful output, where `kmix` is doing something to get the keys working, i place this into my ~/.Xmodmap and run `xmodmap ~/.Xmodmap` when my window manager starts;

Code:

keycode 121 =  XF86AudioMute
keycode 123 =  XF86AudioRaiseVolume
keycode 122 =  XF86AudioLowerVolume

And in my AwesomeWM config i am using this for setting/muting volume;

Code:

    awful.key({ }, "XF86AudioRaiseVolume", function () awful.util.spawn("pactl set-sink-mute 0 false ; pactl set-sink-volume 0 +5%") end),
    awful.key({ }, "XF86AudioLowerVolume", function () awful.util.spawn("pactl set-sink-mute 0 false ; pactl set-sink-volume 0 -5%") end),
    awful.key({ }, "XF86AudioMute", function () awful.util.spawn("pactl set-sink-mute 0 toggle") end),

Yet, this doesn't solve / change anything. As long as a tray utility such as `kmix` isn't running, the keys simply don't register.

Is there something i can do to get these function keys to work correctly without the use of something such as `kmix` ? It seems `kmix` is doing something to properly map these keys, which is simply not set beforehand.

ondoho · 08-18-2019, 02:31 AM

You already identified the problem: kmix (or the K desktop environment) does something to initialise these keys.
I suspect this "something" has something to do with udev or dbus.

Maybe you can try xbindkeys instead of xmodmap:
https://wiki.archlinux.org/index.php/Xbindkeys
Also read:
https://wiki.archlinux.org/index.php..._keyboard_keys

How do you start fluxbox et. al.? through your display manager? or startx?
How do you start KDE? through your display manager? or startx?

coralfang · 08-18-2019, 04:11 AM

Quote:

Originally Posted by ondoho

You already identified the problem: kmix (or the K desktop environment) does something to initialise these keys.
I suspect this "something" has something to do with udev or dbus.

Well yes, but i'm probably asking what exactly it is doing, whether it's something that can be set permanently.

I have had a look at xbindkeys, although that seems to control binds/commands directly, i'd much prefer keybinds to be set from my actual window manager config in the case of AwesomeWM.

All desktop/wm is launched using `startx` also.

On Slackware there is a proper initialisation /etc/X11/xinit/xinitrc.awesome eg;

Code:

#!/bin/sh
# $Xorg: xinitrc.cpp,v 1.3 2000/08/17 19:54:30 cpqbld Exp $

userresources=$HOME/.Xresources
usermodmap=$HOME/.Xmodmap
sysresources=/etc/X11/xinit/.Xresources
sysmodmap=/etc/X11/xinit/.Xmodmap

# merge in defaults and keymaps
[ -f $sysresources ] && xrdb -merge $sysresources
[ -f $sysmodmap ] && xmodmap $sysmodmap
[ -f $userresources ] && xrdb -merge $userresources
[ -f $usermodmap ] && xmodmap $usermodmap

# Start the window manager:
if [ -z "$DESKTOP_SESSION" -a -x /usr/bin/ck-launch-session ]; then
  ck-launch-session dbus-launch --exit-with-session awesome
else
  awesome
fi

ondoho · 08-18-2019, 04:26 AM

Quote:

Originally Posted by coralfang

All desktop/wm is launched using `startx` also.

On Slackware there is a proper initialisation /etc/X11/xinit/xinitrc.awesome eg;

"e.g." meaning you're not actually using it?
Does Slackware use ~/.xinitrc?
On my arch system, I had to add this stanza at some point, otherwise some functionality was missing:

Code:

if [ -d /etc/X11/xinit/xinitrc.d ]
then
  for f in /etc/X11/xinit/xinitrc.d/*
  do
    [ -x "$f" ] && . "$f"
  done
  unset f
fi

coralfang · 08-18-2019, 09:03 AM

Quote:

Originally Posted by ondoho

"e.g." meaning you're not actually using it?
Does Slackware use ~/.xinitrc?
On my arch system, I had to add this stanza at some point, otherwise some functionality was missing:

Code:

if [ -d /etc/X11/xinit/xinitrc.d ]
then
  for f in /etc/X11/xinit/xinitrc.d/*
  do
    [ -x "$f" ] && . "$f"
  done
  unset f
fi

Yes i am using it. Slackware has a tool called xwmconfig to switch. When you select, for eg; "KDE" or "Awesome", it will copy over the correct xinitrc.{plasma,awesome,xfce} to /etc/X11/xinit/xinitrc , so it's contents are being run on my system as for dbus/ck/xmodmap etc.

Code:

$ diff /etc/X11/xinit/xinitrc /etc/X11/xinit/xinitrc.awesome -s
Files /etc/X11/xinit/xinitrc and /etc/X11/xinit/xinitrc.awesome are identical

edit; I also do not personally use a local ~/.xinitrc -- only rely on the /etc/X11/xinitrc/* file.

edit 2; You mention you have an Arch system, do you get the same problem with barebones window managers? As for the WM supporting keybind customization yet XF86Audio* not responding to xev? I recall having the same issue on Arch when i last ran it (although this may be ~2011-2012, a long time ago). Oddly, i've always had the other keys such as XF86Tools, XF86Mail etc, these all work without any additional software.

I might have to skim through kmix source, or even the xfce mixer, to see what's being done to map these key/symbols. I can't see it being much more than a simple udev/dbus command which you previously suggested may be the cause.

ondoho · 08-19-2019, 01:09 AM

Quote:

Originally Posted by coralfang

/etc/X11/xinit/xinitrc , so it's contents are being run

I think you should take a closer look at these contents; compare the content of the KDE one with the content of the one that does NOT work as expected.
Otherwise, it's simply kmix itself - or KDE itself - doing the magic. How to research that?

Quote:

do you get the same problem with barebones window managers? As for the WM supporting keybind customization yet XF86Audio* not responding to xev?

No.
But this is often hardware specific.
Could also be kernel specific (even though KDE does recognize the keys).