On my Acer Aspire 5920G I have touch-buttons to control playback (play/pause, prev, fwd, stop). Since forever they are recognized as mouse-buttons of a second "SynPS/2 Synaptics TouchPad". Normally they would scroll up (button 4), down (5), left (6) or right (7). But I assigned them a slightly different mapping, so that I can actually use them for controlling my music player.

xinput set-button-map `xinput list | grep Synaptics | head -1 | grep -o "id=[[:digit:]]\+" | tr -cd [:digit:]` 1 2 3 17 18 19 20 8 9 10 11 12 13 14 15 16

Since the commit a6de3eac661ff6f23145cdaa49fc722381a1899e in xorg/xserver there is no instant response to these buttons anymore, I have to wait ~0.5s. It's the same case for other scroll-keys, which are located under my touchpad.

This is pretty annoying, as I can't reliably control my music-player anymore. I'm on Arch Linux and downgraded to xorg-server-1.12.2 as a temporal solution.