I just noticed bug #959561 and was curious, so I installed xfce4-mixer and followed the steps to configure the mixer to use the active sound card.
For me, this has solved the volume up and volume down media/function keys. However, the mute key only partially works. It works to mute the volume, but pressing the key again to unmute doesn't work. i.e.: It doesn't toggle between mute and unmute. I have to then resort to unmuting from Volume Control or from the drop down menu of the panel applet. The OSD always reflects the change in state made by all the function keys. The following is the output from configuring the mixer $ xfconf-query -c xfce4-mixer -p /active-card PlaybackRV710730HDMIAudioRadeonHD4000seriesDigitalStereoHDMIPulseAudioMixer $ xfconf-query -c xfce4-mixer -p /sound-card HDAIntelAlsamixer $ xfconf-query -c xfce4-mixer -p /active-card -s `xfconf-query -c xfce4-mixer -p /sound-card` $ xfconf-query -c xfce4-mixer -p /active-card HDAIntelAlsamixer -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/990562 Title: Laptop FN Sound Keys don't update mixer volume To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xfce4-volumed/+bug/990562/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs