Using XF86 Volume keys

Question

I'm in quite a pickle today. As the title suggests, I'd like to use XF86AudioRaiseVolume and XF86AudioLowerVolume keys with sxhkd.

Mapping them in sxhkd doesn't work (the key isn't recognized). Other keys like XF86Sleep works great.

After taking a look at xev, it looks like the key press isn't monitored, only the key release action (although trying to map the release event in sxhkd doesn't work either).

My first hypothesis is that another program is already grabbing keys. Is there any way to know which application is?

-- EDIT --

Other processes seems to fail at binding these keys aswell (except kmix, sometimes). I really believe some process is already capturing these keys, if only I could find out which process it is...

Jaredjarek

What desktop are you using? Consider xfce4-volumed – Uranie

I'm using bspwm, that's why I ask. Pretty much forced to do it manually if I want it to work nicely with statusbar. – Jaredjarek

By the way, if I still try to use xfce4-volumed, I get the warnings : ** (xfce4-volumed:8447): WARNING **: Binding 'XF86AudioRaiseVolume' failed! ** (xfce4-volumed:8447): WARNING **: Binding 'XF86AudioLowerVolume' failed! ** (xfce4-volumed:8447): WARNING **: Binding 'XF86AudioMute' failed! Which is probably another hint that these keys are already captured. I'd really like a way to find out which process is already capturing a certain key. – Jaredjarek

Ask on a bspwm specific forum. – Uranie

This really isn't bspwm specific, and it's an apparently undocumented problem. My question is linux specific, at most X specific. Simply put, how do I determine which process is capturing X key events? – Jaredjarek

You would be better off posting it on unix.stackexchange.com – Nitrogen